glibc, ghc: disable PIE hardening when enabled by default (musl for now :))

[dtzWill]

Motivation for this change

Unbreak after well-intentioned (and IMO the right direct long-term anyway) change
enabling PIE by default when using musl.

Still testing that this fixes GHC, currently the build is past where it failed before
but until it finishes who can say ;).

This fixes GHC! :)

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Fits CONTRIBUTING.md.

---

[dtzWill]

cc #49704 😁

[GrahamcOfBorg]

Success on x86_64-linux (full log)

Attempted: ghc, glibc

Partial log (click to expand)

these paths will be fetched (113.60 MiB download, 1527.56 MiB unpacked):
  /nix/store/b2g750gih0drp1vb68x2si91iwmxqp5c-ghc-8.4.4-doc
  /nix/store/s9a8h6qqdmignsqphir5jyllr5ivf0p3-ghc-8.4.4
copying path '/nix/store/b2g750gih0drp1vb68x2si91iwmxqp5c-ghc-8.4.4-doc' from 'https://nix-cache.s3.amazonaws.com'...
copying path '/nix/store/s9a8h6qqdmignsqphir5jyllr5ivf0p3-ghc-8.4.4' from 'https://nix-cache.s3.amazonaws.com'...
/nix/store/s9a8h6qqdmignsqphir5jyllr5ivf0p3-ghc-8.4.4
/nix/store/g2yk54hifqlsjiha3szr4q3ccmdzyrdv-glibc-2.27

[GrahamcOfBorg]

Success on x86_64-darwin (full log)

Attempted: ghc

The following builds were skipped because they don't evaluate on x86_64-darwin: glibc

Partial log (click to expand)

  { allowUnsupportedSystem = true; }
to ~/.config/nixpkgs/config.nix.


these paths will be fetched (115.65 MiB download, 1288.21 MiB unpacked):
  /nix/store/dxljd69cp3m5cgfl53h0fjbq202m0fm7-ghc-8.4.4
  /nix/store/hyfz6w4rnw2562il2hx9niv1vjlnbsc8-ghc-8.4.4-doc
copying path '/nix/store/hyfz6w4rnw2562il2hx9niv1vjlnbsc8-ghc-8.4.4-doc' from 'https://cache.nixos.org'...
copying path '/nix/store/dxljd69cp3m5cgfl53h0fjbq202m0fm7-ghc-8.4.4' from 'https://cache.nixos.org'...
/nix/store/dxljd69cp3m5cgfl53h0fjbq202m0fm7-ghc-8.4.4

[GrahamcOfBorg]

Failure on aarch64-linux (full log)

Attempted: ghc, glibc

Partial log (click to expand)

        padLiveArgs -- i > regNum ??
CallStack (from HasCallStack):
  error, called at compiler/llvmGen/LlvmCodeGen/Base.hs:194:27 in ghc:LlvmCodeGen.Base

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

make[1]: *** [rts/ghc.mk:295: rts/dist/build/HeapStackCheck.o] Error 1
make: *** [Makefile:127: all] Error 2
builder for '/nix/store/q8naayl1j87njk2cj4ylrn8pxq13jxrn-ghc-8.4.4.drv' failed with exit code 2
error: build of '/nix/store/q8naayl1j87njk2cj4ylrn8pxq13jxrn-ghc-8.4.4.drv' failed

[dtzWill]

Attempting to build anything in the first place suggests aarch64 failure is unrelated/pre-existing. This shouldn't trigger any new builds for non-musl.

[nh2]

Related problem with writeup: #129247 (comment)