Merge #656: remove build.rs for android

Since rust-lang/rust#120593
the minimum android API level is 21.

Related:
https://github.com/android/ndk/wiki/Changelog-r26
rust-lang/rust#129305

1. stop setting `dl_iterate_phdr` based on whether the android API level
    is greater than or equal to 21, but retain it for back compat.
2. remove `cc` build dependency.
3. upgrade ndk r25b to r26d in CI.

Cargo.toml

@@ -2,7 +2,6 @@
 name = "backtrace"
 version = "0.3.73"
 authors = ["The Rust Project Developers"]
-build = "build.rs"
 license = "MIT OR Apache-2.0"
 readme = "README.md"
 repository = "https://github.com/rust-lang/backtrace-rs"
@@ -49,11 +48,6 @@ version = "0.36.0"
 default-features = false
 features = ['read_core', 'elf', 'macho', 'pe', 'xcoff', 'unaligned', 'archive']
 
-[build-dependencies]
-# Only needed for Android, but cannot be target dependent
-# https://github.com/rust-lang/cargo/issues/4932
-cc = "1.0.97"
-
 [dev-dependencies]
 dylib-dep = { path = "crates/dylib-dep" }
 libloading = "0.7"

ci/android-ndk.sh

@@ -1,7 +1,7 @@
 set -ex
 
 ANDROID_NDK_URL=https://dl.google.com/android/repository
-ANDROID_NDK_ARCHIVE=android-ndk-r25b-linux.zip
+ANDROID_NDK_ARCHIVE=android-ndk-r26d-linux.zip
 
 mkdir /android-toolchain
 cd /android-toolchain

ci/docker/arm-linux-androideabi/Dockerfile

@@ -14,5 +14,5 @@ RUN /android-ndk.sh
 ENV PATH=$PATH:/android-toolchain/ndk/toolchains/llvm/prebuilt/linux-x86_64/bin
 
 # TODO: run tests in an emulator eventually
-ENV CARGO_TARGET_ARM_LINUX_ANDROIDEABI_LINKER=armv7a-linux-androideabi19-clang \
+ENV CARGO_TARGET_ARM_LINUX_ANDROIDEABI_LINKER=armv7a-linux-androideabi21-clang \
     CARGO_TARGET_ARM_LINUX_ANDROIDEABI_RUNNER=echo

ci/docker/armv7-linux-androideabi/Dockerfile

@@ -14,5 +14,5 @@ RUN /android-ndk.sh
 ENV PATH=$PATH:/android-toolchain/ndk/toolchains/llvm/prebuilt/linux-x86_64/bin
 
 # TODO: run tests in an emulator eventually
-ENV CARGO_TARGET_ARMV7_LINUX_ANDROIDEABI_LINKER=armv7a-linux-androideabi19-clang \
+ENV CARGO_TARGET_ARMV7_LINUX_ANDROIDEABI_LINKER=armv7a-linux-androideabi21-clang \
     CARGO_TARGET_ARMV7_LINUX_ANDROIDEABI_RUNNER=echo

ci/docker/i686-linux-android/Dockerfile

@@ -14,5 +14,5 @@ RUN /android-ndk.sh
 ENV PATH=$PATH:/android-toolchain/ndk/toolchains/llvm/prebuilt/linux-x86_64/bin
 
 # TODO: run tests in an emulator eventually
-ENV CARGO_TARGET_I686_LINUX_ANDROID_LINKER=i686-linux-android19-clang \
+ENV CARGO_TARGET_I686_LINUX_ANDROID_LINKER=i686-linux-android21-clang \
     CARGO_TARGET_I686_LINUX_ANDROID_RUNNER=echo

crates/as-if-std/Cargo.toml

@@ -28,7 +28,6 @@ features = ['read_core', 'elf', 'macho', 'pe', 'xcoff', 'unaligned', 'archive']
 
 [build-dependencies]
 # Dependency of the `backtrace` crate
-cc = "1.0.97"
 windows-bindgen = "0.56"
 
 [features]

crates/as-if-std/build.rs

@@ -1,11 +1,3 @@
-// backtrace-rs requires a feature check on Android targets, so
-// we need to run its build.rs as well.
-#[allow(unused_extern_crates)]
-#[path = "../../build.rs"]
-mod backtrace_build_rs;
-
 fn main() {
     println!("cargo:rustc-cfg=backtrace_in_libstd");
-
-    backtrace_build_rs::main();
 }

src/symbolize/gimli.rs

@@ -100,7 +100,7 @@ impl Mapping {
             // only borrow `map` and `stash` and we're preserving them below.
             cx: unsafe { core::mem::transmute::<Context<'_>, Context<'static>>(cx) },
             _map: data,
-            stash: stash,
+            stash,
         })
     }
 }
@@ -122,13 +122,11 @@ impl<'data> Context<'data> {
             if cfg!(not(target_os = "aix")) {
                 let data = object.section(stash, id.name()).unwrap_or(&[]);
                 Ok(EndianSlice::new(data, Endian))
+            } else if let Some(name) = id.xcoff_name() {
+                let data = object.section(stash, name).unwrap_or(&[]);
+                Ok(EndianSlice::new(data, Endian))
             } else {
-                if let Some(name) = id.xcoff_name() {
-                    let data = object.section(stash, name).unwrap_or(&[]);
-                    Ok(EndianSlice::new(data, Endian))
-                } else {
-                    Ok(EndianSlice::new(&[], Endian))
-                }
+                Ok(EndianSlice::new(&[], Endian))
             }
         })
         .ok()?;
@@ -226,7 +224,7 @@ cfg_if::cfg_if! {
             target_os = "hurd",
             target_os = "openbsd",
             target_os = "netbsd",
-            all(target_os = "android", feature = "dl_iterate_phdr"),
+            target_os = "android",
         ),
         not(target_env = "uclibc"),
     ))] {