Add android runner to run android binaries.

Android binaries currently fail to run, because `libc++_shared.so` is
not found, so ensure the library is preloaded via `LD_PRELOAD`. This
creates a simple `android-runner` file, so any additional changes can be
added there.

Linked Issues: cross-rs#82

CHANGELOG.md

@@ -7,6 +7,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 - #722 - boolean environment variables are evaluated as truthy or falsey.
 - #721 - add support for running doctests on nightly if `CROSS_UNSTABLE_ENABLE_DOCTESTS=true`.
+- #719 - add android runner to preload `libc++_shared.so`.
 - #718 - remove deb subcommand.
 - #714 - use host target directory when falling back to host cargo.
 - #713 - convert relative target directories to absolute paths.

docker/Dockerfile.aarch64-linux-android

@@ -22,10 +22,12 @@ RUN /qemu.sh aarch64
 
 RUN cp /android-ndk/sysroot/usr/lib/aarch64-linux-android/28/libz.so /system/lib/
 
+COPY android-runner /
+
 # Libz is distributed in the android ndk, but for some unknown reason it is not
 # found in the build process of some crates, so we explicit set the DEP_Z_ROOT
 ENV CARGO_TARGET_AARCH64_LINUX_ANDROID_LINKER=aarch64-linux-android-gcc \
-    CARGO_TARGET_AARCH64_LINUX_ANDROID_RUNNER=qemu-aarch64 \
+    CARGO_TARGET_AARCH64_LINUX_ANDROID_RUNNER="/android-runner aarch64" \
     CC_aarch64_linux_android=aarch64-linux-android-gcc \
     CXX_aarch64_linux_android=aarch64-linux-android-g++ \
     BINDGEN_EXTRA_CLANG_ARGS_aarch64_linux_android="--sysroot=/android-ndk/sysroot" \

docker/Dockerfile.arm-linux-androideabi

@@ -22,10 +22,12 @@ RUN /qemu.sh arm
 
 RUN cp /android-ndk/sysroot/usr/lib/arm-linux-androideabi/28/libz.so /system/lib/
 
+COPY android-runner /
+
 # Libz is distributed in the android ndk, but for some unknown reason it is not
 # found in the build process of some crates, so we explicit set the DEP_Z_ROOT
 ENV CARGO_TARGET_ARM_LINUX_ANDROIDEABI_LINKER=arm-linux-androideabi-gcc \
-    CARGO_TARGET_ARM_LINUX_ANDROIDEABI_RUNNER=qemu-arm \
+    CARGO_TARGET_ARM_LINUX_ANDROIDEABI_RUNNER="/android-runner arm" \
     CC_arm_linux_androideabi=arm-linux-androideabi-gcc \
     CXX_arm_linux_androideabi=arm-linux-androideabi-g++ \
     BINDGEN_EXTRA_CLANG_ARGS_arm_linux_androideabi="--sysroot=/android-ndk/sysroot" \

docker/Dockerfile.i686-linux-android

@@ -29,10 +29,12 @@ RUN /qemu.sh i386
 
 RUN cp /android-ndk/sysroot/usr/lib/i686-linux-android/28/libz.so /system/lib/
 
+COPY android-runner /
+
 # Libz is distributed in the android ndk, but for some unknown reason it is not
 # found in the build process of some crates, so we explicit set the DEP_Z_ROOT
 ENV CARGO_TARGET_I686_LINUX_ANDROID_LINKER=i686-linux-android-gcc \
-    CARGO_TARGET_I686_LINUX_ANDROID_RUNNER="qemu-i386 -cpu n270" \
+    CARGO_TARGET_I686_LINUX_ANDROID_RUNNER="/android-runner i686 -cpu n270" \
     CC_i686_linux_android=i686-linux-android-gcc \
     CXX_i686_linux_android=i686-linux-android-g++ \
     BINDGEN_EXTRA_CLANG_ARGS_i686_linux_android="--sysroot=/android-ndk/sysroot" \

docker/Dockerfile.x86_64-linux-android

@@ -23,10 +23,12 @@ RUN /qemu.sh x86_64
 
 RUN cp /android-ndk/sysroot/usr/lib/x86_64-linux-android/28/libz.so /system/lib/
 
+COPY android-runner /
+
 # Libz is distributed in the android ndk, but for some unknown reason it is not
 # found in the build process of some crates, so we explicit set the DEP_Z_ROOT
 ENV CARGO_TARGET_X86_64_LINUX_ANDROID_LINKER=x86_64-linux-android-gcc \
-    CARGO_TARGET_X86_64_LINUX_ANDROID_RUNNER="qemu-x86_64 -cpu qemu64,+mmx,+sse,+sse2,+sse3,+ssse3,+sse4.1,+sse4.2,+popcnt" \
+    CARGO_TARGET_X86_64_LINUX_ANDROID_RUNNER="/android-runner x86_64 -cpu qemu64,+mmx,+sse,+sse2,+sse3,+ssse3,+sse4.1,+sse4.2,+popcnt" \
     CC_x86_64_linux_android=x86_64-linux-android-gcc \
     CXX_x86_64_linux_android=x86_64-linux-android-g++ \
     BINDGEN_EXTRA_CLANG_ARGS_x86_64_linux_android="--sysroot=/android-ndk/sysroot" \

docker/android-runner

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+set -e
+
+# arch in the rust target
+arch="${1}"
+shift
+
+# select android abi, and find the shared libc++ library
+android_abi="${arch}-linux-android"
+qarch="${arch}"
+case "${arch}" in
+    arm)
+        android_abi="arm-linux-androideabi"
+        ;;
+    i686)
+        qarch="i386"
+        ;;
+esac
+libdir="/android-ndk/sysroot/usr/lib/${android_abi}"
+
+LD_PRELOAD="${libdir}/libc++_shared.so" exec qemu-"${qarch}" "${@}"