From 8d11c1380a8b750bc15641f61590ebc313d754df Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Sun, 4 Jul 2021 21:56:21 +0000
Subject: [PATCH 01/16] pkgsMusl.haskell.compiler.ghc901: Fix evaluation with
 musl

`glibcLocales` only exists when glibc is used.

Similar to commit:

    8727284a - haskell: only use glibcLocales when using glibc
---
 pkgs/development/compilers/ghc/9.0.1.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkgs/development/compilers/ghc/9.0.1.nix b/pkgs/development/compilers/ghc/9.0.1.nix
index f5a6b5f32fa8a..d7db4d66f7457 100644
--- a/pkgs/development/compilers/ghc/9.0.1.nix
+++ b/pkgs/development/compilers/ghc/9.0.1.nix
@@ -143,7 +143,7 @@ stdenv.mkDerivation (rec {
 
     echo -n "${buildMK}" > mk/build.mk
     sed -i -e 's|-isysroot /Developer/SDKs/MacOSX10.5.sdk||' configure
-  '' + lib.optionalString (stdenv.isLinux) ''
+  '' + lib.optionalString (stdenv.isLinux && hostPlatform.libc == "glibc") ''
     export LOCALE_ARCHIVE="${glibcLocales}/lib/locale/locale-archive"
   '' + lib.optionalString (!stdenv.isDarwin) ''
     export NIX_LDFLAGS+=" -rpath $out/lib/ghc-${version}"

From a666b155725da3033fbfae99834bec0b6752911c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Sun, 4 Jul 2021 23:56:19 +0000
Subject: [PATCH 02/16] argp-standalone: Add `-fPIC`.

Fixes `pkgsMusl.elfutils` failing with `recompile with -fPIC`.

This was discovered trying to build `pkgsMusl.haskell.compiler.ghcHEAD`.
---
 pkgs/development/libraries/argp-standalone/default.nix | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/pkgs/development/libraries/argp-standalone/default.nix b/pkgs/development/libraries/argp-standalone/default.nix
index 33b253718a7fb..bb987d069a77f 100644
--- a/pkgs/development/libraries/argp-standalone/default.nix
+++ b/pkgs/development/libraries/argp-standalone/default.nix
@@ -33,7 +33,11 @@ stdenv.mkDerivation {
 
   patchFlags = lib.optional stdenv.hostPlatform.isDarwin "-p0";
 
-  preConfigure = lib.optionalString stdenv.hostPlatform.isLinux "export CFLAGS='-fgnu89-inline'";
+  # For currently unknown reason, `-fPIC` has to be passed explicitly, otherwise
+  # downstream software like `elfutils` will get `recompile errors like:
+  #     libargp.a(argp-help.o): relocation R_X86_64_PC32 against symbol `program_invocation_short_name' can not be used when making a shared object; recompile with -fPIC
+  # It seems that nixpkgs's on-by-default `-fPIC` is not in effect here.
+  preConfigure = lib.optionalString stdenv.hostPlatform.isLinux "export CFLAGS='-fgnu89-inline -fPIC'";
 
   postInstall = ''
     mkdir -p $out/lib $out/include

From 947f757bba6a540272af9339c7ad278bd0bd6c1f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Sun, 4 Jul 2021 17:24:10 +0000
Subject: [PATCH 03/16] haskell.packages.ghc8102Binary: Add comments

---
 pkgs/development/compilers/ghc/8.10.2-binary.nix | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/pkgs/development/compilers/ghc/8.10.2-binary.nix b/pkgs/development/compilers/ghc/8.10.2-binary.nix
index ad1a47e5cc9fe..a0e84c4502be4 100644
--- a/pkgs/development/compilers/ghc/8.10.2-binary.nix
+++ b/pkgs/development/compilers/ghc/8.10.2-binary.nix
@@ -68,8 +68,10 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [ perl ];
   propagatedBuildInputs = lib.optionals useLLVM [ llvmPackages.llvm ];
 
+  # Set LD_LIBRARY_PATH or equivalent so that the programs running as part
+  # of the bindist installer can find the libraries they expect.
   # Cannot patchelf beforehand due to relative RPATHs that anticipate
-  # the final install location/
+  # the final install location.
   ${libEnvVar} = libPath;
 
   postUnpack =
@@ -133,6 +135,7 @@ stdenv.mkDerivation rec {
     "--with-gmp-libraries=${lib.getLib gmp}/lib"
     "--with-gmp-includes=${lib.getDev gmp}/include"
   ] ++ lib.optional stdenv.isDarwin "--with-gcc=${./gcc-clang-wrapper.sh}"
+    # From: https://github.com/NixOS/nixpkgs/pull/43369/commits
     ++ lib.optional stdenv.hostPlatform.isMusl "--disable-ld-override";
 
   # No building is necessary, but calling make without flags ironically

From 67e8744ef8450d6bf6d529ed13dc7172842be425 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Sun, 4 Jul 2021 18:11:47 +0000
Subject: [PATCH 04/16] ghc: Refactor: Extract `ghcBinDists`

---
 .../compilers/ghc/8.10.2-binary.nix           | 71 +++++++++++--------
 1 file changed, 43 insertions(+), 28 deletions(-)

diff --git a/pkgs/development/compilers/ghc/8.10.2-binary.nix b/pkgs/development/compilers/ghc/8.10.2-binary.nix
index a0e84c4502be4..69708add3e1b2 100644
--- a/pkgs/development/compilers/ghc/8.10.2-binary.nix
+++ b/pkgs/development/compilers/ghc/8.10.2-binary.nix
@@ -14,6 +14,47 @@
 assert stdenv.targetPlatform == stdenv.hostPlatform;
 
 let
+  downloadsUrl = "https://downloads.haskell.org/ghc";
+
+  version = "8.10.2";
+
+  # Information about available bindists that we use in the build.
+  ghcBinDists = {
+    i686-linux = {
+      src = {
+        url = "${downloadsUrl}/${version}/ghc-${version}-i386-deb9-linux.tar.xz";
+        sha256 = "0bvwisl4w0z5z8z0da10m9sv0mhm9na2qm43qxr8zl23mn32mblx";
+      };
+    };
+    x86_64-linux = {
+      src = {
+        url = "${downloadsUrl}/${version}/ghc-${version}-x86_64-deb10-linux.tar.xz";
+        sha256 = "0chnzy9j23b2wa8clx5arwz8wnjfxyjmz9qkj548z14cqf13slcl";
+      };
+    };
+    armv7l-linux = {
+      src = {
+        url = "${downloadsUrl}/${version}/ghc-${version}-armv7-deb10-linux.tar.xz";
+        sha256 = "1j41cq5d3rmlgz7hzw8f908fs79gc5mn3q5wz277lk8zdf19g75v";
+      };
+    };
+    aarch64-linux = {
+      src = {
+        url = "${downloadsUrl}/${version}/ghc-${version}-aarch64-deb10-linux.tar.xz";
+        sha256 = "14smwl3741ixnbgi0l51a7kh7xjkiannfqx15b72svky0y4l3wjw";
+      };
+    };
+    x86_64-darwin = {
+      src = {
+        url = "${downloadsUrl}/${version}/ghc-${version}-x86_64-apple-darwin.tar.xz";
+        sha256 = "1hngyq14l4f950hzhh2d204ca2gfc98pc9xdasxihzqd1jq75dzd";
+      };
+    };
+  };
+
+  binDistUsed = ghcBinDists.${stdenv.hostPlatform.system}
+    or (throw "cannot bootstrap GHC on this platform");
+
   useLLVM = !stdenv.targetPlatform.isx86;
 
   libPath = lib.makeLibraryPath ([
@@ -30,40 +71,14 @@ let
        ''"$(cat $NIX_CC/nix-support/dynamic-linker)"''
     else
       "${lib.getLib glibc}/lib/ld-linux*";
-
-  downloadsUrl = "https://downloads.haskell.org/ghc";
-
 in
 
 stdenv.mkDerivation rec {
-  version = "8.10.2";
+  inherit version;
 
   name = "ghc-${version}-binary";
 
-  # https://downloads.haskell.org/~ghc/8.10.2/
-  src = fetchurl ({
-    i686-linux = {
-      url = "${downloadsUrl}/${version}/ghc-${version}-i386-deb9-linux.tar.xz";
-      sha256 = "0bvwisl4w0z5z8z0da10m9sv0mhm9na2qm43qxr8zl23mn32mblx";
-    };
-    x86_64-linux = {
-      url = "${downloadsUrl}/${version}/ghc-${version}-x86_64-deb10-linux.tar.xz";
-      sha256 = "0chnzy9j23b2wa8clx5arwz8wnjfxyjmz9qkj548z14cqf13slcl";
-    };
-    armv7l-linux = {
-      url = "${downloadsUrl}/${version}/ghc-${version}-armv7-deb10-linux.tar.xz";
-      sha256 = "1j41cq5d3rmlgz7hzw8f908fs79gc5mn3q5wz277lk8zdf19g75v";
-    };
-    aarch64-linux = {
-      url = "${downloadsUrl}/${version}/ghc-${version}-aarch64-deb10-linux.tar.xz";
-      sha256 = "14smwl3741ixnbgi0l51a7kh7xjkiannfqx15b72svky0y4l3wjw";
-    };
-    x86_64-darwin = {
-      url = "${downloadsUrl}/${version}/ghc-${version}-x86_64-apple-darwin.tar.xz";
-      sha256 = "1hngyq14l4f950hzhh2d204ca2gfc98pc9xdasxihzqd1jq75dzd";
-    };
-  }.${stdenv.hostPlatform.system}
-    or (throw "cannot bootstrap GHC on this platform"));
+  src = fetchurl binDistUsed.src;
 
   nativeBuildInputs = [ perl ];
   propagatedBuildInputs = lib.optionals useLLVM [ llvmPackages.llvm ];

From 8a2de701f7afb543fb8bd920351715bfabbe7706 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Sun, 4 Jul 2021 18:30:39 +0000
Subject: [PATCH 05/16] haskell.compiler.ghc8102Binary: Fix build on i686.

The library override that was present in the code referred to a
name that isn't even used in current GHC bindists.

Tested with:

    NIX_PATH=nixpkgs=. nix-build --no-link -A haskell.compiler.ghc8102Binary --argstr system i686-linux
---
 pkgs/development/compilers/ghc/8.10.2-binary.nix | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/pkgs/development/compilers/ghc/8.10.2-binary.nix b/pkgs/development/compilers/ghc/8.10.2-binary.nix
index 69708add3e1b2..760c22698681f 100644
--- a/pkgs/development/compilers/ghc/8.10.2-binary.nix
+++ b/pkgs/development/compilers/ghc/8.10.2-binary.nix
@@ -1,5 +1,6 @@
 { lib, stdenv
 , fetchurl, perl, gcc
+, ncurses5
 , ncurses6, gmp, glibc, libiconv, numactl
 , llvmPackages
 
@@ -58,7 +59,11 @@ let
   useLLVM = !stdenv.targetPlatform.isx86;
 
   libPath = lib.makeLibraryPath ([
-    ncurses6 gmp
+    # The i686-linux bindist provided by GHC HQ is currently built on Debian 9,
+    # which link it against `libtinfo.so.5` (ncurses 5).
+    # Other bindists are linked `libtinfo.so.6` (ncurses 6).
+    (if stdenv.hostPlatform.system == "i686-linux" then ncurses5 else ncurses6)
+    gmp
   ] ++ lib.optional (stdenv.hostPlatform.isDarwin) libiconv
     ++ lib.optional (stdenv.hostPlatform.isAarch64) numactl);
 
@@ -124,7 +129,6 @@ stdenv.mkDerivation rec {
     # Rename needed libraries and binaries, fix interpreter
     lib.optionalString stdenv.isLinux ''
       find . -type f -perm -0100 -exec patchelf \
-          --replace-needed libncurses${lib.optionalString stdenv.is64bit "w"}.so.6 libncurses.so \
           --interpreter ${glibcDynLinker} {} \;
 
       sed -i "s|/usr/bin/perl|perl\x00        |" ghc-${version}/ghc/stage2/build/tmp/ghc-stage2

From 1326009806c41950986eeb185f088d4e002dd5c7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Sun, 4 Jul 2021 19:11:42 +0000
Subject: [PATCH 06/16] haskell.compiler.ghc8102Binary: Add check for
 arch-specific libraries.

With this check, we no longer don't notice when the upstream bindist
changes its dependencies (e.g. because a newer Debian version is used
that uses a new `ncurses` version).
---
 .../compilers/ghc/8.10.2-binary.nix           | 92 +++++++++++++++++--
 1 file changed, 83 insertions(+), 9 deletions(-)

diff --git a/pkgs/development/compilers/ghc/8.10.2-binary.nix b/pkgs/development/compilers/ghc/8.10.2-binary.nix
index 760c22698681f..0abb2aa4ac4c6 100644
--- a/pkgs/development/compilers/ghc/8.10.2-binary.nix
+++ b/pkgs/development/compilers/ghc/8.10.2-binary.nix
@@ -20,36 +20,76 @@ let
   version = "8.10.2";
 
   # Information about available bindists that we use in the build.
+  #
+  # # Bindist library checking
+  #
+  # The field `archSpecificLibraries` also provides a way for us get notified
+  # early when the upstream bindist changes its dependencies (e.g. because a
+  # newer Debian version is used that uses a new `ncurses` version).
+  #
+  # Usage:
+  #
+  # * You can find the `fileToCheckFor` of libraries by running `readelf -d`
+  #   on the compiler binary (`exePathForLibraryCheck`).
+  # * To skip library checking for an architecture,
+  #   set `exePathForLibraryCheck = null`.
+  # * To skip file checking for a specific arch specfic library,
+  #   set `fileToCheckFor = null`.
   ghcBinDists = {
     i686-linux = {
       src = {
         url = "${downloadsUrl}/${version}/ghc-${version}-i386-deb9-linux.tar.xz";
         sha256 = "0bvwisl4w0z5z8z0da10m9sv0mhm9na2qm43qxr8zl23mn32mblx";
       };
+      exePathForLibraryCheck = "ghc/stage2/build/tmp/ghc-stage2";
+      archSpecificLibraries = [
+        # The i686-linux bindist provided by GHC HQ is currently built on Debian 9,
+        # which link it against `libtinfo.so.5` (ncurses 5).
+        # Other bindists are linked `libtinfo.so.6` (ncurses 6).
+        { nixPackage = ncurses5; fileToCheckFor = "libtinfo.so.5"; }
+      ];
     };
     x86_64-linux = {
       src = {
         url = "${downloadsUrl}/${version}/ghc-${version}-x86_64-deb10-linux.tar.xz";
         sha256 = "0chnzy9j23b2wa8clx5arwz8wnjfxyjmz9qkj548z14cqf13slcl";
       };
+      exePathForLibraryCheck = "ghc/stage2/build/tmp/ghc-stage2";
+      archSpecificLibraries = [
+        { nixPackage = ncurses6; fileToCheckFor = "libtinfo.so.6"; }
+      ];
     };
     armv7l-linux = {
       src = {
         url = "${downloadsUrl}/${version}/ghc-${version}-armv7-deb10-linux.tar.xz";
         sha256 = "1j41cq5d3rmlgz7hzw8f908fs79gc5mn3q5wz277lk8zdf19g75v";
       };
+      exePathForLibraryCheck = "ghc/stage2/build/tmp/ghc-stage2";
+      archSpecificLibraries = [
+        { nixPackage = ncurses6; fileToCheckFor = "libtinfo.so.6"; }
+      ];
     };
     aarch64-linux = {
       src = {
         url = "${downloadsUrl}/${version}/ghc-${version}-aarch64-deb10-linux.tar.xz";
         sha256 = "14smwl3741ixnbgi0l51a7kh7xjkiannfqx15b72svky0y4l3wjw";
       };
+      exePathForLibraryCheck = "ghc/stage2/build/tmp/ghc-stage2";
+      archSpecificLibraries = [
+        { nixPackage = ncurses6; fileToCheckFor = "libtinfo.so.6"; }
+        { nixPackage = numactl; fileToCheckFor = null; }
+      ];
     };
     x86_64-darwin = {
       src = {
         url = "${downloadsUrl}/${version}/ghc-${version}-x86_64-apple-darwin.tar.xz";
         sha256 = "1hngyq14l4f950hzhh2d204ca2gfc98pc9xdasxihzqd1jq75dzd";
       };
+      exePathForLibraryCheck = null; # we don't have a library check for darwin yet
+      archSpecificLibraries = [
+        { nixPackage = ncurses6; fileToCheckFor = null; }
+        { nixPackage = libiconv; fileToCheckFor = null; }
+      ];
     };
   };
 
@@ -58,14 +98,14 @@ let
 
   useLLVM = !stdenv.targetPlatform.isx86;
 
-  libPath = lib.makeLibraryPath ([
-    # The i686-linux bindist provided by GHC HQ is currently built on Debian 9,
-    # which link it against `libtinfo.so.5` (ncurses 5).
-    # Other bindists are linked `libtinfo.so.6` (ncurses 6).
-    (if stdenv.hostPlatform.system == "i686-linux" then ncurses5 else ncurses6)
-    gmp
-  ] ++ lib.optional (stdenv.hostPlatform.isDarwin) libiconv
-    ++ lib.optional (stdenv.hostPlatform.isAarch64) numactl);
+  libPath =
+    lib.makeLibraryPath (
+      [
+        gmp
+      ]
+      # Add arch-specific libraries.
+      ++ map ({ nixPackage, ... }: nixPackage) binDistUsed.archSpecificLibraries
+    );
 
   libEnvVar = lib.optionalString stdenv.hostPlatform.isDarwin "DY"
     + "LD_LIBRARY_PATH";
@@ -95,9 +135,43 @@ stdenv.mkDerivation rec {
   ${libEnvVar} = libPath;
 
   postUnpack =
+    # Verify our assumptions of which `libtinfo.so` (ncurses) version is used,
+    # so that we know when ghc bindists upgrade that and we need to update the
+    # version used in `libPath`.
+    lib.optionalString
+      (binDistUsed.exePathForLibraryCheck != null)
+      # Note the `*` glob because some GHCs have a suffix when unpacked, e.g.
+      # the musl bindist has dir `ghc-VERSION-x86_64-unknown-linux/`.
+      # As a result, don't shell-quote this glob when splicing the string.
+      (let buildExeGlob = ''ghc-${version}*/"${binDistUsed.exePathForLibraryCheck}"''; in
+        lib.concatStringsSep "\n" [
+          (''
+            echo "Checking that ghc binary exists in bindist at ${buildExeGlob}"
+            if ! test -e ${buildExeGlob}; then
+              echo >&2 "GHC binary ${binDistUsed.exePathForLibraryCheck} could not be found in the bindist build directory (at ${buildExeGlob}) for arch ${stdenv.hostPlatform.system}, please check that ghcBinDists correctly reflect the bindist dependencies!"; exit 1;
+            fi
+          '')
+          (lib.concatMapStringsSep
+            "\n"
+            ({ fileToCheckFor, nixPackage }:
+              lib.optionalString (fileToCheckFor != null) ''
+                echo "Checking bindist for ${fileToCheckFor} to ensure that is still used"
+                if ! readelf -d ${buildExeGlob} | grep "${fileToCheckFor}"; then
+                  echo >&2 "File ${fileToCheckFor} could not be found in ${binDistUsed.exePathForLibraryCheck} for arch ${stdenv.hostPlatform.system}, please check that ghcBinDists correctly reflect the bindist dependencies!"; exit 1;
+                fi
+
+                echo "Checking that the nix package ${nixPackage} contains ${fileToCheckFor}"
+                if ! test -e "${lib.getLib nixPackage}/lib/${fileToCheckFor}"; then
+                  echo >&2 "Nix package ${nixPackage} did not contain ${fileToCheckFor} for arch ${stdenv.hostPlatform.system}, please check that ghcBinDists correctly reflect the bindist dependencies!"; exit 1;
+                fi
+              ''
+            )
+            binDistUsed.archSpecificLibraries
+          )
+        ])
     # GHC has dtrace probes, which causes ld to try to open /usr/lib/libdtrace.dylib
     # during linking
-    lib.optionalString stdenv.isDarwin ''
+    + lib.optionalString stdenv.isDarwin ''
       export NIX_LDFLAGS+=" -no_dtrace_dof"
       # not enough room in the object files for the full path to libiconv :(
       for exe in $(find . -type f -executable); do

From 5777bd3d561d955a0cce9a46d6bf545ee40ba84c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Sun, 4 Jul 2021 19:24:06 +0000
Subject: [PATCH 07/16] haskell.compiler.ghc8102Binary: Remove `sed` of
 `/usr/bin/*` commands.

None of the current bindists appear to contain these paths in their
`ghc-stage2` binary.
---
 pkgs/development/compilers/ghc/8.10.2-binary.nix | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/pkgs/development/compilers/ghc/8.10.2-binary.nix b/pkgs/development/compilers/ghc/8.10.2-binary.nix
index 0abb2aa4ac4c6..51d57f6f8410e 100644
--- a/pkgs/development/compilers/ghc/8.10.2-binary.nix
+++ b/pkgs/development/compilers/ghc/8.10.2-binary.nix
@@ -204,9 +204,6 @@ stdenv.mkDerivation rec {
     lib.optionalString stdenv.isLinux ''
       find . -type f -perm -0100 -exec patchelf \
           --interpreter ${glibcDynLinker} {} \;
-
-      sed -i "s|/usr/bin/perl|perl\x00        |" ghc-${version}/ghc/stage2/build/tmp/ghc-stage2
-      sed -i "s|/usr/bin/gcc|gcc\x00        |" ghc-${version}/ghc/stage2/build/tmp/ghc-stage2
     '' +
     # We're kludging a glibc bindist into working with non-glibc...
     # Here we patch up the use of `__strdup` (part of glibc binary ABI)

From da1cf8cb90c6675356106905422bbbe767261e9b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Sun, 4 Jul 2021 19:26:53 +0000
Subject: [PATCH 08/16] pkgsMusl.haskell.compiler.ghc8102Binary: Fix musl
 segfault. Fixes #118731 #129247.

This commit replaces the musl + glibc hackery in the GHC bindist
compiler by using the new musl based bindist that GHC HQ provides
(built on Alpine).
We could alternatively also use a nix-built musl boostrap compiler,
but it seems nicer to use the GHC HQ one for now.

This fixes the compiler built by
`pkgsMusl.haskell.compiler.ghc8102Binary` segfaulting (#118731)
since the commit

    5e2311d2f - musl: 1.2.1 -> 1.2.2

concretely, musl commit

    01c7920f - remove redundant pthread struct members repeated for layout purposes

which I suspect breaks some glibc/musl ABI compatibility that may have
existed accidentally until then.

The added

    lib.optional stdenv.targetPlatform.isMusl "pie";

also fixes that the packaged bindist compiler cannot create a binary
in its `installCheck` phase (and overall); see detail explanation
in #129247.
---
 .../compilers/ghc/8.10.2-binary.nix           | 105 +++++++++++++-----
 1 file changed, 76 insertions(+), 29 deletions(-)

diff --git a/pkgs/development/compilers/ghc/8.10.2-binary.nix b/pkgs/development/compilers/ghc/8.10.2-binary.nix
index 51d57f6f8410e..a2a7f7b9eaced 100644
--- a/pkgs/development/compilers/ghc/8.10.2-binary.nix
+++ b/pkgs/development/compilers/ghc/8.10.2-binary.nix
@@ -1,7 +1,7 @@
 { lib, stdenv
 , fetchurl, perl, gcc
 , ncurses5
-, ncurses6, gmp, glibc, libiconv, numactl
+, ncurses6, gmp, libiconv, numactl
 , llvmPackages
 
   # minimal = true; will remove files that aren't strictly necessary for
@@ -49,16 +49,33 @@ let
         { nixPackage = ncurses5; fileToCheckFor = "libtinfo.so.5"; }
       ];
     };
-    x86_64-linux = {
-      src = {
-        url = "${downloadsUrl}/${version}/ghc-${version}-x86_64-deb10-linux.tar.xz";
-        sha256 = "0chnzy9j23b2wa8clx5arwz8wnjfxyjmz9qkj548z14cqf13slcl";
-      };
-      exePathForLibraryCheck = "ghc/stage2/build/tmp/ghc-stage2";
-      archSpecificLibraries = [
-        { nixPackage = ncurses6; fileToCheckFor = "libtinfo.so.6"; }
-      ];
-    };
+    x86_64-linux =
+      if stdenv.hostPlatform.isMusl
+        then
+          { # musl-bindist (referred to below)
+            src = {
+              url = "${downloadsUrl}/${version}/ghc-${version}-x86_64-alpine3.10-linux-integer-simple.tar.xz";
+              sha256 = "0xpcbyaxqyhbl6f0i3s4rp2jm67nqpkfh2qlbj3i2fiaix89ml0l";
+            };
+            exePathForLibraryCheck = "bin/ghc";
+            archSpecificLibraries = [
+              # In contrast to glibc builds, the musl-bindist uses `libncursesw.so.*`
+              # instead of `libtinfo.so.*.`
+              { nixPackage = ncurses6; fileToCheckFor = "libncursesw.so.6"; }
+            ];
+          }
+        else
+          { # normal glibc based bindist
+            src = {
+              url = "${downloadsUrl}/${version}/ghc-${version}-x86_64-deb10-linux.tar.xz";
+              sha256 = "0chnzy9j23b2wa8clx5arwz8wnjfxyjmz9qkj548z14cqf13slcl";
+            };
+            exePathForLibraryCheck = "ghc/stage2/build/tmp/ghc-stage2";
+            archSpecificLibraries = [
+              { nixPackage = ncurses6; fileToCheckFor = "libtinfo.so.6"; }
+            ];
+          }
+        ;
     armv7l-linux = {
       src = {
         url = "${downloadsUrl}/${version}/ghc-${version}-armv7-deb10-linux.tar.xz";
@@ -110,12 +127,6 @@ let
   libEnvVar = lib.optionalString stdenv.hostPlatform.isDarwin "DY"
     + "LD_LIBRARY_PATH";
 
-  glibcDynLinker = assert stdenv.isLinux;
-    if stdenv.hostPlatform.libc == "glibc" then
-       # Could be stdenv.cc.bintools.dynamicLinker, keeping as-is to avoid rebuild.
-       ''"$(cat $NIX_CC/nix-support/dynamic-linker)"''
-    else
-      "${lib.getLib glibc}/lib/ld-linux*";
 in
 
 stdenv.mkDerivation rec {
@@ -126,7 +137,20 @@ stdenv.mkDerivation rec {
   src = fetchurl binDistUsed.src;
 
   nativeBuildInputs = [ perl ];
-  propagatedBuildInputs = lib.optionals useLLVM [ llvmPackages.llvm ];
+  propagatedBuildInputs =
+    lib.optionals useLLVM [ llvmPackages.llvm ]
+    # Because musl bindists currently provide no way to tell where
+    # libgmp is (see not [musl bindists have no .buildinfo]), we need
+    # to propagate `gmp`, otherwise programs built by this ghc will
+    # fail linking with `cannot find -lgmp` errors.
+    # Also, as of writing, the release pages of musl bindists claim
+    # that they use `integer-simple` and do not require `gmp`; however
+    # that is incorrect, so `gmp` is required until a release has been
+    # made that includes https://gitlab.haskell.org/ghc/ghc/-/issues/20059.
+    # (Note that for packaging the `-binary` compiler, nixpkgs does not care
+    # about whether or not `gmp` is used; this comment is just here to explain
+    # why the `gmp` dependency exists despite what the release page says.)
+    ++ lib.optionals stdenv.hostPlatform.isMusl [ gmp ]; # musl bindist needs this
 
   # Set LD_LIBRARY_PATH or equivalent so that the programs running as part
   # of the bindist installer can find the libraries they expect.
@@ -187,6 +211,9 @@ stdenv.mkDerivation rec {
       patchShebangs ghc-${version}/configure
     '' +
     # We have to patch the GMP paths for the integer-gmp package.
+    # Note [musl bindists have no .buildinfo]
+    # Note that musl bindists do not contain them; unclear if that's intended;
+    # see: https://gitlab.haskell.org/ghc/ghc/-/issues/20073#note_363231
     ''
       find . -name integer-gmp.buildinfo \
           -exec sed -i "s@extra-lib-dirs: @extra-lib-dirs: ${gmp.out}/lib@" {} \;
@@ -203,16 +230,7 @@ stdenv.mkDerivation rec {
     # Rename needed libraries and binaries, fix interpreter
     lib.optionalString stdenv.isLinux ''
       find . -type f -perm -0100 -exec patchelf \
-          --interpreter ${glibcDynLinker} {} \;
-    '' +
-    # We're kludging a glibc bindist into working with non-glibc...
-    # Here we patch up the use of `__strdup` (part of glibc binary ABI)
-    # to instead use `strdup` since musl doesn't provide __strdup
-    # (`__strdup` is defined to be an alias of `strdup` anyway[1]).
-    # [1] http://refspecs.linuxbase.org/LSB_4.0.0/LSB-Core-generic/LSB-Core-generic/baselib---strdup-1.html
-    # Use objcopy magic to make the change:
-    lib.optionalString stdenv.hostPlatform.isMusl ''
-      find ./ghc-${version}/rts -name "libHSrts*.a" -exec ''${OBJCOPY:-objcopy} --redefine-sym __strdup=strdup {} \;
+          --interpreter ${stdenv.cc.bintools.dynamicLinker} {} \;
     '';
 
   # fix for `configure: error: Your linker is affected by binutils #16177`
@@ -222,6 +240,9 @@ stdenv.mkDerivation rec {
 
   configurePlatforms = [ ];
   configureFlags = [
+    # Note that musl-based bindists seem to do nothing with the
+    # `--with-gmp-libraries` flag, see:
+    # https://gitlab.haskell.org/ghc/ghc/-/issues/20073#note_363231
     "--with-gmp-libraries=${lib.getLib gmp}/lib"
     "--with-gmp-includes=${lib.getDev gmp}/include"
   ] ++ lib.optional stdenv.isDarwin "--with-gcc=${./gcc-clang-wrapper.sh}"
@@ -232,6 +253,22 @@ stdenv.mkDerivation rec {
   # calls install-strip ...
   dontBuild = true;
 
+  # Apparently necessary for the ghc Alpine (musl) bindist:
+  # When we strip, and then run the
+  #     patchelf --set-rpath "${libPath}:$(patchelf --print-rpath $p)" $p
+  # below, running ghc (e.g. during `installCheckPhase)` gives some apparently
+  # corrupted rpath or whatever makes the loader work on nonsensical strings:
+  #     running install tests
+  #     Error relocating /nix/store/...-ghc-8.10.2-binary/lib/ghc-8.10.5/bin/ghc: : symbol not found
+  #     Error relocating /nix/store/...-ghc-8.10.2-binary/lib/ghc-8.10.5/bin/ghc: ir6zf6c9f86pfx8sr30n2vjy-ghc-8.10.2-binary/lib/ghc-8.10.5/bin/../lib/x86_64-linux-ghc-8.10.5/libHSexceptions-0.10.4-ghc8.10.5.so: symbol not found
+  #     Error relocating /nix/store/...-ghc-8.10.2-binary/lib/ghc-8.10.5/bin/ghc: y/lib/ghc-8.10.5/bin/../lib/x86_64-linux-ghc-8.10.5/libHStemplate-haskell-2.16.0.0-ghc8.10.5.so: symbol not found
+  #     Error relocating /nix/store/...-ghc-8.10.2-binary/lib/ghc-8.10.5/bin/ghc: 8.10.5/libHStemplate-haskell-2.16.0.0-ghc8.10.5.so: symbol not found
+  #     Error relocating /nix/store/...-ghc-8.10.2-binary/lib/ghc-8.10.5/bin/ghc: �: symbol not found
+  #     Error relocating /nix/store/...-ghc-8.10.2-binary/lib/ghc-8.10.5/bin/ghc: �?: symbol not found
+  #     Error relocating /nix/store/...-ghc-8.10.2-binary/lib/ghc-8.10.5/bin/ghc: 64-linux-ghc-8.10.5/libHSexceptions-0.10.4-ghc8.10.5.so: symbol not found
+  # This is extremely bogus and should be investigated.
+  dontStrip = if stdenv.hostPlatform.isMusl then true else false; # `if` for explicitness
+
   # On Linux, use patchelf to modify the executables so that they can
   # find editline/gmp.
   postFixup = lib.optionalString stdenv.isLinux
@@ -279,13 +316,23 @@ stdenv.mkDerivation rec {
     find $out -type f -name '*.p_o' -delete
     find $out -type f -name '*.p_hi' -delete
     find $out -type f -name '*_p.a' -delete
-    rm $out/lib/ghc-*/bin/ghc-iserv-prof
+    # `-f` because e.g. musl bindist does not have this file.
+    rm -f $out/lib/ghc-*/bin/ghc-iserv-prof
     # Hydra will redistribute this derivation, so we have to keep the docs for
     # legal reasons (retaining the legal notices etc)
     # As a last resort we could unpack the docs separately and symlink them in.
     # They're in $out/share/{doc,man}.
   '';
 
+  # In nixpkgs, musl based builds currently enable `pie` hardening by default
+  # (see `defaultHardeningFlags` in `make-derivation.nix`).
+  # But GHC cannot currently produce outputs that are ready for `-pie` linking.
+  # Thus, disable `pie` hardening, otherwise `recompile with -fPIE` errors appear.
+  # See:
+  # * https://github.com/NixOS/nixpkgs/issues/129247
+  # * https://gitlab.haskell.org/ghc/ghc/-/issues/19580
+  hardeningDisable = lib.optional stdenv.targetPlatform.isMusl "pie";
+
   doInstallCheck = true;
   installCheckPhase = ''
     unset ${libEnvVar}

From c866b8a13b881fe2082fb05998173a0408b9177f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Sun, 4 Jul 2021 21:42:15 +0000
Subject: [PATCH 09/16] haskell.compiler.ghc8102Binary: find `-executable` ->
 `-perm -0100`

---
 pkgs/development/compilers/ghc/8.10.2-binary.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkgs/development/compilers/ghc/8.10.2-binary.nix b/pkgs/development/compilers/ghc/8.10.2-binary.nix
index a2a7f7b9eaced..d77a9601deeda 100644
--- a/pkgs/development/compilers/ghc/8.10.2-binary.nix
+++ b/pkgs/development/compilers/ghc/8.10.2-binary.nix
@@ -229,7 +229,7 @@ stdenv.mkDerivation rec {
     '' +
     # Rename needed libraries and binaries, fix interpreter
     lib.optionalString stdenv.isLinux ''
-      find . -type f -perm -0100 -exec patchelf \
+      find . -type f -executable -exec patchelf \
           --interpreter ${stdenv.cc.bintools.dynamicLinker} {} \;
     '';
 

From f154c3addec162c89b8c256da17129c1a7a7d7fe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Sun, 4 Jul 2021 21:44:23 +0000
Subject: [PATCH 10/16] haskell.compiler.ghc865Binary: Disable "pie" hardening.
 See #129247

While this does not fix `ghc865Binary` with musl, it at least prevents
that the other, newer errors are shadowed (see #129247).
---
 pkgs/development/compilers/ghc/8.6.5-binary.nix | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/pkgs/development/compilers/ghc/8.6.5-binary.nix b/pkgs/development/compilers/ghc/8.6.5-binary.nix
index 8a0994b8b6a54..42b60ec32312b 100644
--- a/pkgs/development/compilers/ghc/8.6.5-binary.nix
+++ b/pkgs/development/compilers/ghc/8.6.5-binary.nix
@@ -152,6 +152,15 @@ stdenv.mkDerivation rec {
     done
   '';
 
+  # In nixpkgs, musl based builds currently enable `pie` hardening by default
+  # (see `defaultHardeningFlags` in `make-derivation.nix`).
+  # But GHC cannot currently produce outputs that are ready for `-pie` linking.
+  # Thus, disable `pie` hardening, otherwise `recompile with -fPIE` errors appear.
+  # See:
+  # * https://github.com/NixOS/nixpkgs/issues/129247
+  # * https://gitlab.haskell.org/ghc/ghc/-/issues/19580
+  hardeningDisable = lib.optional stdenv.targetPlatform.isMusl "pie";
+
   doInstallCheck = true;
   installCheckPhase = ''
     unset ${libEnvVar}

From 8b15fccf8ae1dfb0c9404e46b9b008d15f6a372d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Sun, 4 Jul 2021 21:48:18 +0000
Subject: [PATCH 11/16] pkgsMuslhaskell.compiler.{ghc884,ghc8104}: Use GHC 8.10
 as bootstrap compiler.

This addresses the fact that `ghc865Binary` segfaults on musl
(see #118731) because of the glibc+musl mix used in there.

With the previous commits, `ghc8102Binary` was changed to use
the musl-based bindist from GHC HQ instead, which works.

With this change, all nix Haskell compilers builds on musl:

    NIX_PATH=nixpkgs=. nix-build --no-link --expr 'with import <nixpkgs> {}; { inherit (pkgsMusl.haskell.compiler) ghc884 ghc8104 ghc901 ghcHEAD; }'
---
 pkgs/development/compilers/ghc/8.8.4.nix | 11 +++++++----
 pkgs/top-level/haskell-packages.nix      |  6 ++++--
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/pkgs/development/compilers/ghc/8.8.4.nix b/pkgs/development/compilers/ghc/8.8.4.nix
index 544b96f5e4f03..c907928d5ef9c 100644
--- a/pkgs/development/compilers/ghc/8.8.4.nix
+++ b/pkgs/development/compilers/ghc/8.8.4.nix
@@ -142,11 +142,14 @@ stdenv.mkDerivation (rec {
   postPatch = "patchShebangs .";
 
   # GHC is a bit confused on its cross terminology.
-  preConfigure = lib.optionalString stdenv.isAarch64 ''
+  preConfigure =
     # Aarch64 allow backward bootstrapping since earlier versions are unstable.
-    find . -name \*\.cabal\* -exec sed -i -e 's/\(base.*\)4.14/\14.16/' {} \; \
-      -exec sed -i -e 's/\(prim.*\)0.6/\10.8/' {} \;
-  '' + ''
+    # Same for musl, as earlier versions do not provide a musl bindist for bootstrapping.
+    lib.optionalString (stdenv.isAarch64 || stdenv.hostPlatform.isMusl) ''
+      find . -name \*\.cabal\* -exec sed -i -e 's/\(base.*\)4.14/\14.16/' {} \; \
+        -exec sed -i -e 's/\(prim.*\)0.6/\10.8/' {} \;
+    ''
+  + ''
     for env in $(env | grep '^TARGET_' | sed -E 's|\+?=.*||'); do
       export "''${env#TARGET_}=''${!env}"
     done
diff --git a/pkgs/top-level/haskell-packages.nix b/pkgs/top-level/haskell-packages.nix
index 8bea40efe64d4..b872f3286e162 100644
--- a/pkgs/top-level/haskell-packages.nix
+++ b/pkgs/top-level/haskell-packages.nix
@@ -57,7 +57,8 @@ in {
 
     ghc884 = callPackage ../development/compilers/ghc/8.8.4.nix {
       # aarch64 ghc865Binary gets SEGVs due to haskell#15449 or similar
-      bootPkgs = if stdenv.isAarch64 then
+      # Musl bindists do not exist for ghc 8.6.5, so we use 8.10.* for them
+      bootPkgs = if stdenv.isAarch64 || stdenv.targetPlatform.isMusl then
           packages.ghc8102BinaryMinimal
         else
           packages.ghc865Binary;
@@ -67,7 +68,8 @@ in {
     };
     ghc8104 = callPackage ../development/compilers/ghc/8.10.4.nix {
       # aarch64 ghc865Binary gets SEGVs due to haskell#15449 or similar
-      bootPkgs = if stdenv.isAarch64 || stdenv.isAarch32 then
+      # Musl bindists do not exist for ghc 8.6.5, so we use 8.10.* for them
+      bootPkgs = if stdenv.isAarch64 || stdenv.isAarch32 || stdenv.targetPlatform.isMusl then
           packages.ghc8102BinaryMinimal
         else
           packages.ghc865Binary;

From 8adcd395041665bad739f777e7b6284186a4c507 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Sun, 4 Jul 2021 21:59:24 +0000
Subject: [PATCH 12/16] ghc: Add comments about `hardeningDisable` `pie` for
 musl

---
 pkgs/development/compilers/ghc/8.10.4.nix | 11 ++++++++++-
 pkgs/development/compilers/ghc/8.8.4.nix  | 11 ++++++++++-
 pkgs/development/compilers/ghc/9.0.1.nix  | 11 ++++++++++-
 pkgs/development/compilers/ghc/head.nix   | 11 ++++++++++-
 4 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/pkgs/development/compilers/ghc/8.10.4.nix b/pkgs/development/compilers/ghc/8.10.4.nix
index f007dcf789875..8062062f42b41 100644
--- a/pkgs/development/compilers/ghc/8.10.4.nix
+++ b/pkgs/development/compilers/ghc/8.10.4.nix
@@ -238,7 +238,16 @@ stdenv.mkDerivation (rec {
 
   checkTarget = "test";
 
-  hardeningDisable = [ "format" ] ++ lib.optional stdenv.targetPlatform.isMusl "pie";
+  hardeningDisable =
+    [ "format" ]
+    # In nixpkgs, musl based builds currently enable `pie` hardening by default
+    # (see `defaultHardeningFlags` in `make-derivation.nix`).
+    # But GHC cannot currently produce outputs that are ready for `-pie` linking.
+    # Thus, disable `pie` hardening, otherwise `recompile with -fPIE` errors appear.
+    # See:
+    # * https://github.com/NixOS/nixpkgs/issues/129247
+    # * https://gitlab.haskell.org/ghc/ghc/-/issues/19580
+    ++ lib.optional stdenv.targetPlatform.isMusl "pie";
 
   postInstall = ''
     # Install the bash completion file.
diff --git a/pkgs/development/compilers/ghc/8.8.4.nix b/pkgs/development/compilers/ghc/8.8.4.nix
index c907928d5ef9c..1f643d53be4f0 100644
--- a/pkgs/development/compilers/ghc/8.8.4.nix
+++ b/pkgs/development/compilers/ghc/8.8.4.nix
@@ -248,7 +248,16 @@ stdenv.mkDerivation (rec {
 
   checkTarget = "test";
 
-  hardeningDisable = [ "format" ] ++ lib.optional stdenv.targetPlatform.isMusl "pie";
+  hardeningDisable =
+    [ "format" ]
+    # In nixpkgs, musl based builds currently enable `pie` hardening by default
+    # (see `defaultHardeningFlags` in `make-derivation.nix`).
+    # But GHC cannot currently produce outputs that are ready for `-pie` linking.
+    # Thus, disable `pie` hardening, otherwise `recompile with -fPIE` errors appear.
+    # See:
+    # * https://github.com/NixOS/nixpkgs/issues/129247
+    # * https://gitlab.haskell.org/ghc/ghc/-/issues/19580
+    ++ lib.optional stdenv.targetPlatform.isMusl "pie";
 
   postInstall = ''
     # Install the bash completion file.
diff --git a/pkgs/development/compilers/ghc/9.0.1.nix b/pkgs/development/compilers/ghc/9.0.1.nix
index d7db4d66f7457..f461fa6d4403d 100644
--- a/pkgs/development/compilers/ghc/9.0.1.nix
+++ b/pkgs/development/compilers/ghc/9.0.1.nix
@@ -225,7 +225,16 @@ stdenv.mkDerivation (rec {
 
   checkTarget = "test";
 
-  hardeningDisable = [ "format" ] ++ lib.optional stdenv.targetPlatform.isMusl "pie";
+  hardeningDisable =
+    [ "format" ]
+    # In nixpkgs, musl based builds currently enable `pie` hardening by default
+    # (see `defaultHardeningFlags` in `make-derivation.nix`).
+    # But GHC cannot currently produce outputs that are ready for `-pie` linking.
+    # Thus, disable `pie` hardening, otherwise `recompile with -fPIE` errors appear.
+    # See:
+    # * https://github.com/NixOS/nixpkgs/issues/129247
+    # * https://gitlab.haskell.org/ghc/ghc/-/issues/19580
+    ++ lib.optional stdenv.targetPlatform.isMusl "pie";
 
   postInstall = ''
     # Install the bash completion file.
diff --git a/pkgs/development/compilers/ghc/head.nix b/pkgs/development/compilers/ghc/head.nix
index ec236731afd7c..18df8c538d738 100644
--- a/pkgs/development/compilers/ghc/head.nix
+++ b/pkgs/development/compilers/ghc/head.nix
@@ -242,7 +242,16 @@ stdenv.mkDerivation (rec {
 
   checkTarget = "test";
 
-  hardeningDisable = [ "format" ] ++ lib.optional stdenv.targetPlatform.isMusl "pie";
+  hardeningDisable =
+    [ "format" ]
+    # In nixpkgs, musl based builds currently enable `pie` hardening by default
+    # (see `defaultHardeningFlags` in `make-derivation.nix`).
+    # But GHC cannot currently produce outputs that are ready for `-pie` linking.
+    # Thus, disable `pie` hardening, otherwise `recompile with -fPIE` errors appear.
+    # See:
+    # * https://github.com/NixOS/nixpkgs/issues/129247
+    # * https://gitlab.haskell.org/ghc/ghc/-/issues/19580
+    ++ lib.optional stdenv.targetPlatform.isMusl "pie";
 
   postInstall = ''
     # Install the bash completion file.

From f4e62a996f82f2e52c988097c828ff227d93f1be Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Sun, 4 Jul 2021 22:07:57 +0000
Subject: [PATCH 13/16] pkgsMusl.haskell.compiler.ghc{8104,884,901,HEAD}:
 Disable sphinx for musl

Adds new package options:

* enableDocs
* enableHaddockProgram

to control whether to build Sphinx docs, and GHC haddocks and the
haddock program.

Unfortunately currently the building of the `haddock `program
and generating GHC docs are mixed into one option, see:
https://gitlab.haskell.org/ghc/ghc/-/issues/20077

Making Sphinx docs disableable, and disabling them by default
for Musl and cross builds, makes it much easier to provide these
builds without having to support Sphinx's enormous dependency
tree for those ways of building.
---
 pkgs/development/compilers/ghc/8.10.4.nix | 40 ++++++++++++++++++++---
 pkgs/development/compilers/ghc/8.8.4.nix  | 40 ++++++++++++++++++++---
 pkgs/development/compilers/ghc/9.0.1.nix  | 40 ++++++++++++++++++++---
 pkgs/development/compilers/ghc/head.nix   | 40 ++++++++++++++++++++---
 4 files changed, 144 insertions(+), 16 deletions(-)

diff --git a/pkgs/development/compilers/ghc/8.10.4.nix b/pkgs/development/compilers/ghc/8.10.4.nix
index 8062062f42b41..10ca2f6662c27 100644
--- a/pkgs/development/compilers/ghc/8.10.4.nix
+++ b/pkgs/development/compilers/ghc/8.10.4.nix
@@ -38,6 +38,20 @@
   ghcFlavour ? lib.optionalString (stdenv.targetPlatform != stdenv.hostPlatform)
     (if useLLVM then "perf-cross" else "perf-cross-ncg")
 
+, #  Whether to build sphinx documentation.
+  enableDocs ? (
+    # Docs disabled for musl and cross because it's a large task to keep
+    # all `sphinx` dependencies building in those environments.
+    # `sphinx` pulls in among others:
+    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
+    (stdenv.targetPlatform == stdenv.hostPlatform)
+    && !stdenv.hostPlatform.isMusl
+  )
+
+, enableHaddockProgram ?
+    # Disabled for cross; see note [HADDOCK_DOCS].
+    (stdenv.targetPlatform == stdenv.hostPlatform)
+
 , # Whether to disable the large address space allocator
   # necessary fix for iOS: https://www.reddit.com/r/haskell/comments/4ttdz1/building_an_osxi386_to_iosarm64_cross_compiler/d5qvd67/
   disableLargeAddressSpace ? stdenv.targetPlatform.isDarwin && stdenv.targetPlatform.isAarch64
@@ -45,6 +59,10 @@
 
 assert !enableIntegerSimple -> gmp != null;
 
+# Cross cannot currently build the `haddock` program for silly reasons,
+# see note [HADDOCK_DOCS].
+assert (stdenv.targetPlatform != stdenv.hostPlatform) -> !enableHaddockProgram;
+
 let
   inherit (stdenv) buildPlatform hostPlatform targetPlatform;
 
@@ -60,14 +78,26 @@ let
     ifneq \"\$(BuildFlavour)\" \"\"
     include mk/flavours/\$(BuildFlavour).mk
     endif
+    BUILD_SPHINX_HTML = ${if enableDocs then "YES" else "NO"}
+    BUILD_SPHINX_PDF = NO
+  '' +
+  # Note [HADDOCK_DOCS]:
+  # Unfortunately currently `HADDOCK_DOCS` controls both whether the `haddock`
+  # program is built (which we generally always want to have a complete GHC install)
+  # and whether it is run on the GHC sources to generate hyperlinked source code
+  # (which is impossible for cross-compilation); see:
+  # https://gitlab.haskell.org/ghc/ghc/-/issues/20077
+  # This implies that currently a cross-compiled GHC will never have a `haddock`
+  # program, so it can never generate haddocks for any packages.
+  # If this is solved in the future, we'd like to unconditionally
+  # build the haddock program (removing the `enableHaddockProgram` option).
+  ''
+    HADDOCK_DOCS = ${if enableHaddockProgram then "YES" else "NO"}
     DYNAMIC_GHC_PROGRAMS = ${if enableShared then "YES" else "NO"}
     INTEGER_LIBRARY = ${if enableIntegerSimple then "integer-simple" else "integer-gmp"}
   '' + lib.optionalString (targetPlatform != hostPlatform) ''
     Stage1Only = ${if targetPlatform.system == hostPlatform.system then "NO" else "YES"}
     CrossCompilePrefix = ${targetPrefix}
-    HADDOCK_DOCS = NO
-    BUILD_SPHINX_HTML = NO
-    BUILD_SPHINX_PDF = NO
   '' + lib.optionalString (!enableProfiledLibs) ''
     GhcLibWays = "v dyn"
   '' + lib.optionalString enableRelocatedStaticLibs ''
@@ -217,8 +247,10 @@ stdenv.mkDerivation (rec {
   dontAddExtraLibs = true;
 
   nativeBuildInputs = [
-    perl autoconf automake m4 python3 sphinx
+    perl autoconf automake m4 python3
     ghc bootPkgs.alex bootPkgs.happy bootPkgs.hscolour
+  ] ++ lib.optionals enableDocs [
+    sphinx
   ];
 
   # For building runtime libs
diff --git a/pkgs/development/compilers/ghc/8.8.4.nix b/pkgs/development/compilers/ghc/8.8.4.nix
index 1f643d53be4f0..238266147167e 100644
--- a/pkgs/development/compilers/ghc/8.8.4.nix
+++ b/pkgs/development/compilers/ghc/8.8.4.nix
@@ -38,6 +38,20 @@
   ghcFlavour ? lib.optionalString (stdenv.targetPlatform != stdenv.hostPlatform)
     (if useLLVM then "perf-cross" else "perf-cross-ncg")
 
+, #  Whether to build sphinx documentation.
+  enableDocs ? (
+    # Docs disabled for musl and cross because it's a large task to keep
+    # all `sphinx` dependencies building in those environments.
+    # `sphinx` pullls in among others:
+    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
+    (stdenv.targetPlatform == stdenv.hostPlatform)
+    && !stdenv.hostPlatform.isMusl
+  )
+
+, enableHaddockProgram ?
+    # Disabled for cross; see note [HADDOCK_DOCS].
+    (stdenv.targetPlatform == stdenv.hostPlatform)
+
 , # Whether to disable the large address space allocator
   # necessary fix for iOS: https://www.reddit.com/r/haskell/comments/4ttdz1/building_an_osxi386_to_iosarm64_cross_compiler/d5qvd67/
   disableLargeAddressSpace ? stdenv.targetPlatform.isDarwin && stdenv.targetPlatform.isAarch64
@@ -45,6 +59,10 @@
 
 assert !enableIntegerSimple -> gmp != null;
 
+# Cross cannot currently build the `haddock` program for silly reasons,
+# see note [HADDOCK_DOCS].
+assert (stdenv.targetPlatform != stdenv.hostPlatform) -> !enableHaddockProgram;
+
 let
   inherit (stdenv) buildPlatform hostPlatform targetPlatform;
 
@@ -60,6 +78,21 @@ let
     ifneq \"\$(BuildFlavour)\" \"\"
     include mk/flavours/\$(BuildFlavour).mk
     endif
+    BUILD_SPHINX_HTML = ${if enableDocs then "YES" else "NO"}
+    BUILD_SPHINX_PDF = NO
+  '' +
+  # Note [HADDOCK_DOCS]:
+  # Unfortunately currently `HADDOCK_DOCS` controls both whether the `haddock`
+  # program is built (which we generally always want to have a complete GHC install)
+  # and whether it is run on the GHC sources to generate hyperlinked source code
+  # (which is impossible for cross-compilation); see:
+  # https://gitlab.haskell.org/ghc/ghc/-/issues/20077
+  # This implies that currently a cross-compiled GHC will never have a `haddock`
+  # program, so it can never generate haddocks for any packages.
+  # If this is solved in the future, we'd like to unconditionally
+  # build the haddock program (removing the `enableHaddockProgram` option).
+  ''
+    HADDOCK_DOCS = ${if enableHaddockProgram then "YES" else "NO"}
     DYNAMIC_GHC_PROGRAMS = ${if enableShared then "YES" else "NO"}
     INTEGER_LIBRARY = ${if enableIntegerSimple then "integer-simple" else "integer-gmp"}
   ''
@@ -72,9 +105,6 @@ let
   + lib.optionalString (targetPlatform != hostPlatform) ''
     Stage1Only = ${if (targetPlatform.system == hostPlatform.system && !targetPlatform.isiOS) then "NO" else "YES"}
     CrossCompilePrefix = ${targetPrefix}
-    HADDOCK_DOCS = NO
-    BUILD_SPHINX_HTML = NO
-    BUILD_SPHINX_PDF = NO
   '' + lib.optionalString dontStrip ''
     STRIP_CMD = :
   '' + lib.optionalString (!enableProfiledLibs) ''
@@ -227,8 +257,10 @@ stdenv.mkDerivation (rec {
   dontAddExtraLibs = true;
 
   nativeBuildInputs = [
-    perl autoconf automake m4 python3 sphinx
+    perl autoconf automake m4 python3
     ghc bootPkgs.alex bootPkgs.happy bootPkgs.hscolour
+  ] ++ lib.optionals enableDocs [
+    sphinx
   ];
 
   # For building runtime libs
diff --git a/pkgs/development/compilers/ghc/9.0.1.nix b/pkgs/development/compilers/ghc/9.0.1.nix
index f461fa6d4403d..d2ae51c66dee2 100644
--- a/pkgs/development/compilers/ghc/9.0.1.nix
+++ b/pkgs/development/compilers/ghc/9.0.1.nix
@@ -39,6 +39,20 @@
   ghcFlavour ? lib.optionalString (stdenv.targetPlatform != stdenv.hostPlatform)
     (if useLLVM then "perf-cross" else "perf-cross-ncg")
 
+, #  Whether to build sphinx documentation.
+  enableDocs ? (
+    # Docs disabled for musl and cross because it's a large task to keep
+    # all `sphinx` dependencies building in those environments.
+    # `sphinx` pullls in among others:
+    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
+    (stdenv.targetPlatform == stdenv.hostPlatform)
+    && !stdenv.hostPlatform.isMusl
+  )
+
+, enableHaddockProgram ?
+    # Disabled for cross; see note [HADDOCK_DOCS].
+    (stdenv.targetPlatform == stdenv.hostPlatform)
+
 , # Whether to disable the large address space allocator
   # necessary fix for iOS: https://www.reddit.com/r/haskell/comments/4ttdz1/building_an_osxi386_to_iosarm64_cross_compiler/d5qvd67/
   disableLargeAddressSpace ? stdenv.targetPlatform.isDarwin && stdenv.targetPlatform.isAarch64
@@ -46,6 +60,10 @@
 
 assert !enableIntegerSimple -> gmp != null;
 
+# Cross cannot currently build the `haddock` program for silly reasons,
+# see note [HADDOCK_DOCS].
+assert (stdenv.targetPlatform != stdenv.hostPlatform) -> !enableHaddockProgram;
+
 let
   inherit (stdenv) buildPlatform hostPlatform targetPlatform;
 
@@ -61,14 +79,26 @@ let
     ifneq \"\$(BuildFlavour)\" \"\"
     include mk/flavours/\$(BuildFlavour).mk
     endif
+    BUILD_SPHINX_HTML = ${if enableDocs then "YES" else "NO"}
+    BUILD_SPHINX_PDF = NO
+  '' +
+  # Note [HADDOCK_DOCS]:
+  # Unfortunately currently `HADDOCK_DOCS` controls both whether the `haddock`
+  # program is built (which we generally always want to have a complete GHC install)
+  # and whether it is run on the GHC sources to generate hyperlinked source code
+  # (which is impossible for cross-compilation); see:
+  # https://gitlab.haskell.org/ghc/ghc/-/issues/20077
+  # This implies that currently a cross-compiled GHC will never have a `haddock`
+  # program, so it can never generate haddocks for any packages.
+  # If this is solved in the future, we'd like to unconditionally
+  # build the haddock program (removing the `enableHaddockProgram` option).
+  ''
+    HADDOCK_DOCS = ${if enableHaddockProgram then "YES" else "NO"}
     DYNAMIC_GHC_PROGRAMS = ${if enableShared then "YES" else "NO"}
     INTEGER_LIBRARY = ${if enableIntegerSimple then "integer-simple" else "integer-gmp"}
   '' + lib.optionalString (targetPlatform != hostPlatform) ''
     Stage1Only = ${if targetPlatform.system == hostPlatform.system then "NO" else "YES"}
     CrossCompilePrefix = ${targetPrefix}
-    HADDOCK_DOCS = NO
-    BUILD_SPHINX_HTML = NO
-    BUILD_SPHINX_PDF = NO
   '' + lib.optionalString (!enableProfiledLibs) ''
     GhcLibWays = "v dyn"
   '' + lib.optionalString enableRelocatedStaticLibs ''
@@ -204,8 +234,10 @@ stdenv.mkDerivation (rec {
   dontAddExtraLibs = true;
 
   nativeBuildInputs = [
-    perl autoconf automake m4 python3 sphinx
+    perl autoconf automake m4 python3
     ghc bootPkgs.alex bootPkgs.happy bootPkgs.hscolour
+  ] ++ lib.optionals enableDocs [
+    sphinx
   ];
 
   # For building runtime libs
diff --git a/pkgs/development/compilers/ghc/head.nix b/pkgs/development/compilers/ghc/head.nix
index 18df8c538d738..2ea14b78cc4a1 100644
--- a/pkgs/development/compilers/ghc/head.nix
+++ b/pkgs/development/compilers/ghc/head.nix
@@ -46,6 +46,20 @@
   ghcFlavour ? lib.optionalString (stdenv.targetPlatform != stdenv.hostPlatform)
     (if useLLVM then "perf-cross" else "perf-cross-ncg")
 
+, #  Whether to build sphinx documentation.
+  enableDocs ? (
+    # Docs disabled for musl and cross because it's a large task to keep
+    # all `sphinx` dependencies building in those environments.
+    # `sphinx` pullls in among others:
+    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
+    (stdenv.targetPlatform == stdenv.hostPlatform)
+    && !stdenv.hostPlatform.isMusl
+  )
+
+, enableHaddockProgram ?
+    # Disabled for cross; see note [HADDOCK_DOCS].
+    (stdenv.targetPlatform == stdenv.hostPlatform)
+
 , # Whether to disable the large address space allocator
   # necessary fix for iOS: https://www.reddit.com/r/haskell/comments/4ttdz1/building_an_osxi386_to_iosarm64_cross_compiler/d5qvd67/
   disableLargeAddressSpace ? stdenv.targetPlatform.isDarwin && stdenv.targetPlatform.isAarch64
@@ -53,6 +67,10 @@
 
 assert !enableNativeBignum -> gmp != null;
 
+# Cross cannot currently build the `haddock` program for silly reasons,
+# see note [HADDOCK_DOCS].
+assert (stdenv.targetPlatform != stdenv.hostPlatform) -> !enableHaddockProgram;
+
 let
   inherit (stdenv) buildPlatform hostPlatform targetPlatform;
 
@@ -68,14 +86,26 @@ let
     ifneq \"\$(BuildFlavour)\" \"\"
     include mk/flavours/\$(BuildFlavour).mk
     endif
+    BUILD_SPHINX_HTML = ${if enableDocs then "YES" else "NO"}
+    BUILD_SPHINX_PDF = NO
+  '' +
+  # Note [HADDOCK_DOCS]:
+  # Unfortunately currently `HADDOCK_DOCS` controls both whether the `haddock`
+  # program is built (which we generally always want to have a complete GHC install)
+  # and whether it is run on the GHC sources to generate hyperlinked source code
+  # (which is impossible for cross-compilation); see:
+  # https://gitlab.haskell.org/ghc/ghc/-/issues/20077
+  # This implies that currently a cross-compiled GHC will never have a `haddock`
+  # program, so it can never generate haddocks for any packages.
+  # If this is solved in the future, we'd like to unconditionally
+  # build the haddock program (removing the `enableHaddockProgram` option).
+  ''
+    HADDOCK_DOCS = ${if enableHaddockProgram then "YES" else "NO"}
     DYNAMIC_GHC_PROGRAMS = ${if enableShared then "YES" else "NO"}
     BIGNUM_BACKEND = ${if enableNativeBignum then "native" else "gmp"}
   '' + lib.optionalString (targetPlatform != hostPlatform) ''
     Stage1Only = ${if (targetPlatform.system == hostPlatform.system && !targetPlatform.isiOS) then "NO" else "YES"}
     CrossCompilePrefix = ${targetPrefix}
-    HADDOCK_DOCS = NO
-    BUILD_SPHINX_HTML = NO
-    BUILD_SPHINX_PDF = NO
   '' + lib.optionalString dontStrip ''
     STRIP_CMD = :
   '' + lib.optionalString (!enableProfiledLibs) ''
@@ -221,8 +251,10 @@ stdenv.mkDerivation (rec {
   dontAddExtraLibs = true;
 
   nativeBuildInputs = [
-    perl autoconf autoreconfHook automake m4 python3 sphinx
+    perl autoconf autoreconfHook automake m4 python3
     ghc bootPkgs.alex bootPkgs.happy bootPkgs.hscolour
+  ] ++ lib.optionals enableDocs [
+    sphinx
   ];
 
   # For building runtime libs

From c6a77590e30fb16450ed666b39cd1b8daf8ca2ae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Mon, 5 Jul 2021 17:08:58 +0200
Subject: [PATCH 14/16] haskell.compiler.ghc8102Binary: Split `ghcBinDists` set
 into default and musl.

This allows to implement the "HACK" mentioned in the commit to
build `pkgsMusl` GHCs on Hydra without failing evaluation on Darwin.

Reference of the discussion:
https://github.com/NixOS/nixpkgs/pull/129289#discussion_r663956747

Patch contributed by @sterni.
---
 .../compilers/ghc/8.10.2-binary.nix           | 151 ++++++++++--------
 1 file changed, 82 insertions(+), 69 deletions(-)

diff --git a/pkgs/development/compilers/ghc/8.10.2-binary.nix b/pkgs/development/compilers/ghc/8.10.2-binary.nix
index d77a9601deeda..616b2894bb3b6 100644
--- a/pkgs/development/compilers/ghc/8.10.2-binary.nix
+++ b/pkgs/development/compilers/ghc/8.10.2-binary.nix
@@ -36,82 +36,86 @@ let
   # * To skip file checking for a specific arch specfic library,
   #   set `fileToCheckFor = null`.
   ghcBinDists = {
-    i686-linux = {
-      src = {
-        url = "${downloadsUrl}/${version}/ghc-${version}-i386-deb9-linux.tar.xz";
-        sha256 = "0bvwisl4w0z5z8z0da10m9sv0mhm9na2qm43qxr8zl23mn32mblx";
+    # Binary distributions for the default libc (e.g. glibc, or libSystem on Darwin)
+    # nixpkgs uses for the respective system.
+    defaultLibc = {
+      i686-linux = {
+        src = {
+          url = "${downloadsUrl}/${version}/ghc-${version}-i386-deb9-linux.tar.xz";
+          sha256 = "0bvwisl4w0z5z8z0da10m9sv0mhm9na2qm43qxr8zl23mn32mblx";
+        };
+        exePathForLibraryCheck = "ghc/stage2/build/tmp/ghc-stage2";
+        archSpecificLibraries = [
+          # The i686-linux bindist provided by GHC HQ is currently built on Debian 9,
+          # which link it against `libtinfo.so.5` (ncurses 5).
+          # Other bindists are linked `libtinfo.so.6` (ncurses 6).
+          { nixPackage = ncurses5; fileToCheckFor = "libtinfo.so.5"; }
+        ];
       };
-      exePathForLibraryCheck = "ghc/stage2/build/tmp/ghc-stage2";
-      archSpecificLibraries = [
-        # The i686-linux bindist provided by GHC HQ is currently built on Debian 9,
-        # which link it against `libtinfo.so.5` (ncurses 5).
-        # Other bindists are linked `libtinfo.so.6` (ncurses 6).
-        { nixPackage = ncurses5; fileToCheckFor = "libtinfo.so.5"; }
-      ];
-    };
-    x86_64-linux =
-      if stdenv.hostPlatform.isMusl
-        then
-          { # musl-bindist (referred to below)
-            src = {
-              url = "${downloadsUrl}/${version}/ghc-${version}-x86_64-alpine3.10-linux-integer-simple.tar.xz";
-              sha256 = "0xpcbyaxqyhbl6f0i3s4rp2jm67nqpkfh2qlbj3i2fiaix89ml0l";
-            };
-            exePathForLibraryCheck = "bin/ghc";
-            archSpecificLibraries = [
-              # In contrast to glibc builds, the musl-bindist uses `libncursesw.so.*`
-              # instead of `libtinfo.so.*.`
-              { nixPackage = ncurses6; fileToCheckFor = "libncursesw.so.6"; }
-            ];
-          }
-        else
-          { # normal glibc based bindist
-            src = {
-              url = "${downloadsUrl}/${version}/ghc-${version}-x86_64-deb10-linux.tar.xz";
-              sha256 = "0chnzy9j23b2wa8clx5arwz8wnjfxyjmz9qkj548z14cqf13slcl";
-            };
-            exePathForLibraryCheck = "ghc/stage2/build/tmp/ghc-stage2";
-            archSpecificLibraries = [
-              { nixPackage = ncurses6; fileToCheckFor = "libtinfo.so.6"; }
-            ];
-          }
-        ;
-    armv7l-linux = {
-      src = {
-        url = "${downloadsUrl}/${version}/ghc-${version}-armv7-deb10-linux.tar.xz";
-        sha256 = "1j41cq5d3rmlgz7hzw8f908fs79gc5mn3q5wz277lk8zdf19g75v";
+      x86_64-linux = {
+        src = {
+          url = "${downloadsUrl}/${version}/ghc-${version}-x86_64-deb10-linux.tar.xz";
+          sha256 = "0chnzy9j23b2wa8clx5arwz8wnjfxyjmz9qkj548z14cqf13slcl";
+        };
+        exePathForLibraryCheck = "ghc/stage2/build/tmp/ghc-stage2";
+        archSpecificLibraries = [
+          { nixPackage = ncurses6; fileToCheckFor = "libtinfo.so.6"; }
+        ];
       };
-      exePathForLibraryCheck = "ghc/stage2/build/tmp/ghc-stage2";
-      archSpecificLibraries = [
-        { nixPackage = ncurses6; fileToCheckFor = "libtinfo.so.6"; }
-      ];
-    };
-    aarch64-linux = {
-      src = {
-        url = "${downloadsUrl}/${version}/ghc-${version}-aarch64-deb10-linux.tar.xz";
-        sha256 = "14smwl3741ixnbgi0l51a7kh7xjkiannfqx15b72svky0y4l3wjw";
+      armv7l-linux = {
+        src = {
+          url = "${downloadsUrl}/${version}/ghc-${version}-armv7-deb10-linux.tar.xz";
+          sha256 = "1j41cq5d3rmlgz7hzw8f908fs79gc5mn3q5wz277lk8zdf19g75v";
+        };
+        exePathForLibraryCheck = "ghc/stage2/build/tmp/ghc-stage2";
+        archSpecificLibraries = [
+          { nixPackage = ncurses6; fileToCheckFor = "libtinfo.so.6"; }
+        ];
+      };
+      aarch64-linux = {
+        src = {
+          url = "${downloadsUrl}/${version}/ghc-${version}-aarch64-deb10-linux.tar.xz";
+          sha256 = "14smwl3741ixnbgi0l51a7kh7xjkiannfqx15b72svky0y4l3wjw";
+        };
+        exePathForLibraryCheck = "ghc/stage2/build/tmp/ghc-stage2";
+        archSpecificLibraries = [
+          { nixPackage = ncurses6; fileToCheckFor = "libtinfo.so.6"; }
+          { nixPackage = numactl; fileToCheckFor = null; }
+        ];
+      };
+      x86_64-darwin = {
+        src = {
+          url = "${downloadsUrl}/${version}/ghc-${version}-x86_64-apple-darwin.tar.xz";
+          sha256 = "1hngyq14l4f950hzhh2d204ca2gfc98pc9xdasxihzqd1jq75dzd";
+        };
+        exePathForLibraryCheck = null; # we don't have a library check for darwin yet
+        archSpecificLibraries = [
+          { nixPackage = ncurses6; fileToCheckFor = null; }
+          { nixPackage = libiconv; fileToCheckFor = null; }
+        ];
       };
-      exePathForLibraryCheck = "ghc/stage2/build/tmp/ghc-stage2";
-      archSpecificLibraries = [
-        { nixPackage = ncurses6; fileToCheckFor = "libtinfo.so.6"; }
-        { nixPackage = numactl; fileToCheckFor = null; }
-      ];
     };
-    x86_64-darwin = {
-      src = {
-        url = "${downloadsUrl}/${version}/ghc-${version}-x86_64-apple-darwin.tar.xz";
-        sha256 = "1hngyq14l4f950hzhh2d204ca2gfc98pc9xdasxihzqd1jq75dzd";
+    # Binary distributions for the musl libc for the respective system.
+    musl = {
+      x86_64-linux = {
+        src = {
+          url = "${downloadsUrl}/${version}/ghc-${version}-x86_64-alpine3.10-linux-integer-simple.tar.xz";
+          sha256 = "0xpcbyaxqyhbl6f0i3s4rp2jm67nqpkfh2qlbj3i2fiaix89ml0l";
+        };
+        exePathForLibraryCheck = "bin/ghc";
+        archSpecificLibraries = [
+          # In contrast to glibc builds, the musl-bindist uses `libncursesw.so.*`
+          # instead of `libtinfo.so.*.`
+          { nixPackage = ncurses6; fileToCheckFor = "libncursesw.so.6"; }
+        ];
       };
-      exePathForLibraryCheck = null; # we don't have a library check for darwin yet
-      archSpecificLibraries = [
-        { nixPackage = ncurses6; fileToCheckFor = null; }
-        { nixPackage = libiconv; fileToCheckFor = null; }
-      ];
     };
   };
 
-  binDistUsed = ghcBinDists.${stdenv.hostPlatform.system}
-    or (throw "cannot bootstrap GHC on this platform");
+  distSetName = if stdenv.hostPlatform.isMusl then "musl" else "defaultLibc";
+
+  binDistUsed = ghcBinDists.${distSetName}.${stdenv.hostPlatform.system}
+    or (throw "cannot bootstrap GHC on this platform ('${stdenv.hostPlatform.system}' with libc '${distSetName}')");
 
   useLLVM = !stdenv.targetPlatform.isx86;
 
@@ -361,7 +365,16 @@ stdenv.mkDerivation rec {
     homepage = "http://haskell.org/ghc";
     description = "The Glasgow Haskell Compiler";
     license = lib.licenses.bsd3;
-    platforms = ["x86_64-linux" "armv7l-linux" "aarch64-linux" "i686-linux" "x86_64-darwin"];
+    # HACK: since we can't encode the libc / abi in platforms, we need
+    # to make the platform list dependent on the evaluation platform
+    # in order to avoid eval errors with musl which supports less
+    # platforms than the default libcs (i. e. glibc / libSystem).
+    # This is done for the benefit of Hydra, so `packagePlatforms`
+    # won't return any platforms that would cause an evaluation
+    # failure for `pkgsMusl.haskell.compiler.ghc8102Binary`, as
+    # long as the evaluator runs on a platform that supports
+    # `pkgsMusl`.
+    platforms = builtins.attrNames ghcBinDists.${distSetName};
     hydraPlatforms = builtins.filter (p: minimal || p != "aarch64-linux") platforms;
     maintainers = with lib.maintainers; [ lostnet ];
   };

From 0044356dc7b53fbafb78ceb17cec05e293c70940 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Mon, 5 Jul 2021 01:32:25 +0000
Subject: [PATCH 15/16] release-haskell.nix: Add pkgsMusl haskell compilers to
 Hydra jobs

---
 pkgs/top-level/release-haskell.nix | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/pkgs/top-level/release-haskell.nix b/pkgs/top-level/release-haskell.nix
index 87a08dddb606b..bf26526872bbb 100644
--- a/pkgs/top-level/release-haskell.nix
+++ b/pkgs/top-level/release-haskell.nix
@@ -96,6 +96,8 @@ let
         writers = testPlatforms.writers;
       };
 
+      pkgsMusl.haskell.compiler = packagePlatforms pkgs.pkgsMusl.haskell.compiler;
+
       # test some statically linked packages to catch regressions
       # and get some cache going for static compilation with GHC
       pkgsStatic.haskellPackages = {
@@ -308,6 +310,21 @@ let
           jobs.pkgsStatic.haskellPackages.random.aarch64-linux
         ];
       };
+      muslGHCs = pkgs.releaseTools.aggregate {
+        name = "haskell-pkgsMusl-ghcs";
+        meta = {
+          description = "GHCs built with musl";
+          maintainers = with lib.maintainers; [
+            nh2
+          ];
+        };
+        constituents = accumulateDerivations [
+          jobs.pkgsMusl.haskell.compiler.ghc8102Binary
+          jobs.pkgsMusl.haskell.compiler.ghc884
+          jobs.pkgsMusl.haskell.compiler.ghc8104
+          jobs.pkgsMusl.haskell.compiler.ghc901
+        ];
+      };
     }
   ];
 

From 63b1e6e48990c01ce0dcfbceb850047a2c24cbda Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Mon, 5 Jul 2021 19:01:00 +0200
Subject: [PATCH 16/16] ghc*-binary: Remove no-op `--with-gmp-libraries`

---
 pkgs/development/compilers/ghc/8.10.2-binary.nix | 6 ++----
 pkgs/development/compilers/ghc/8.6.5-binary.nix  | 3 ++-
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/pkgs/development/compilers/ghc/8.10.2-binary.nix b/pkgs/development/compilers/ghc/8.10.2-binary.nix
index 616b2894bb3b6..3ef4ebb9b98f7 100644
--- a/pkgs/development/compilers/ghc/8.10.2-binary.nix
+++ b/pkgs/development/compilers/ghc/8.10.2-binary.nix
@@ -244,11 +244,9 @@ stdenv.mkDerivation rec {
 
   configurePlatforms = [ ];
   configureFlags = [
-    # Note that musl-based bindists seem to do nothing with the
-    # `--with-gmp-libraries` flag, see:
-    # https://gitlab.haskell.org/ghc/ghc/-/issues/20073#note_363231
-    "--with-gmp-libraries=${lib.getLib gmp}/lib"
     "--with-gmp-includes=${lib.getDev gmp}/include"
+    # Note `--with-gmp-libraries` does nothing for GHC bindists:
+    # https://gitlab.haskell.org/ghc/ghc/-/merge_requests/6124
   ] ++ lib.optional stdenv.isDarwin "--with-gcc=${./gcc-clang-wrapper.sh}"
     # From: https://github.com/NixOS/nixpkgs/pull/43369/commits
     ++ lib.optional stdenv.hostPlatform.isMusl "--disable-ld-override";
diff --git a/pkgs/development/compilers/ghc/8.6.5-binary.nix b/pkgs/development/compilers/ghc/8.6.5-binary.nix
index 42b60ec32312b..c3d6ab1beca2f 100644
--- a/pkgs/development/compilers/ghc/8.6.5-binary.nix
+++ b/pkgs/development/compilers/ghc/8.6.5-binary.nix
@@ -121,8 +121,9 @@ stdenv.mkDerivation rec {
 
   configurePlatforms = [ ];
   configureFlags = [
-    "--with-gmp-libraries=${lib.getLib gmp}/lib"
     "--with-gmp-includes=${lib.getDev gmp}/include"
+    # Note `--with-gmp-libraries` does nothing for GHC bindists:
+    # https://gitlab.haskell.org/ghc/ghc/-/merge_requests/6124
   ] ++ lib.optional stdenv.isDarwin "--with-gcc=${./gcc-clang-wrapper.sh}"
     ++ lib.optional stdenv.hostPlatform.isMusl "--disable-ld-override";