First hack at adding C and linker flags to our CMake config, for Android-arm

Author: joakim-noah

runtime/CMakeLists.txt

@@ -40,12 +40,27 @@ set(COMPILE_ALL_D_FILES_AT_ONCE ON                            CACHE BOOL   "Comp
 set(RT_CFLAGS             ""                                  CACHE STRING "Runtime extra C compiler flags, separated by ' '")
 set(LD_FLAGS              ""                                  CACHE STRING "Runtime extra C linker flags, separated by ' '")
 set(C_SYSTEM_LIBS         AUTO                                CACHE STRING "C system libraries for linking shared libraries and test runners, separated by ';'")
-set(TARGET_SYSTEM         AUTO                                CACHE STRING "Targeted platform for cross-compilation (e.g., 'Linux;UNIX', 'Darwin;APPLE;UNIX', 'Windows;MSVC')")
+set(TARGET_SYSTEM         AUTO                                CACHE STRING "Target OS/toolchain for cross-compilation (e.g., 'Linux;UNIX', 'Darwin;APPLE;UNIX', 'Windows;MSVC')")
+set(TARGET_PLATFORM       AUTO                                CACHE STRING "Target platform for cross-compilation, shortcut variable with format OS-arch (e.g., 'Linux-arm', 'Mac-x64', 'Windows-aarch64', 'Android-x86')")
 
 set(CMAKE_INSTALL_LIBDIR ${CMAKE_INSTALL_PREFIX}/lib${LIB_SUFFIX})
 
+if(RT_CFLAGS STREQUAL "" AND "${TARGET_PLATFORM}" MATCHES "Android")
+    set(RT_CFLAGS_UNCONFIGURED True)
+    if("${TARGET_PLATFORM}" MATCHES "arm")
+        set(RT_CFLAGS "-fpic -ffunction-sections -funwind-tables -fstack-protector-strong -Wno-invalid-command-line-argument -Wno-unused-command-line-argument -no-canonical-prefixes -target armv7-none-linux-androideabi -march=armv7-a -mfloat-abi=softfp -mfpu=vfpv3-d16 -mthumb -Os -g -DNDEBUG -fomit-frame-pointer -fno-strict-aliasing -DANDROID -Wa,--noexecstack -Wformat -Werror=format-security")
+    endif()
+endif()
+
+if(LD_FLAGS STREQUAL "" AND "${TARGET_PLATFORM}" MATCHES "Android")
+    set(LD_FLAGS_UNCONFIGURED True)
+    if("${TARGET_PLATFORM}" MATCHES "arm")
+        set(LD_FLAGS "-Wl,-z,nocopyreloc -lgcc -target armv7-none-linux-androideabi -no-canonical-prefixes -Wl,--fix-cortex-a8 -Wl,--no-undefined -Wl,-z,noexecstack -Wl,-z,relro -Wl,-z,now -Wl,--warn-shared-textrel -Wl,--fatal-warnings -fPIE -pie")
+    endif()
+endif()
+
 # Auto-detect TARGET_SYSTEM
-if("${TARGET_SYSTEM}" STREQUAL "AUTO")
+if("${TARGET_PLATFORM}" STREQUAL "AUTO")
     set(TARGET_SYSTEM ${CMAKE_SYSTEM_NAME})
     # Additionally add MSVC, APPLE and/or UNIX
     if(MSVC)
@@ -57,6 +72,26 @@ if("${TARGET_SYSTEM}" STREQUAL "AUTO")
     if(UNIX)
         list(APPEND TARGET_SYSTEM "UNIX")
     endif()
+else()
+    if("${TARGET_PLATFORM}" MATCHES "Windows")
+        set(TARGET_SYSTEM "Windows;MSVC")
+        if("${TARGET_PLATFORM}" MATCHES "x64")
+            # stub example, fill in with the rest
+            list(APPEND D_FLAGS "-mtriple=x86_64-pc-windows-msvc")
+        endif()
+    elseif("${TARGET_PLATFORM}" MATCHES "Android")
+        set(TARGET_SYSTEM "Android;Linux;UNIX")
+        set(ANDROID_API "21")
+        if("${TARGET_PLATFORM}" MATCHES "arm")
+            list(APPEND D_FLAGS "-mtriple=armv7-none-linux-android")
+            if (RT_CFLAGS_UNCONFIGURED AND NOT CMAKE_SYSTEM_PROCESSOR MATCHES "arm")
+                append("-gcc-toolchain $ENV{NDK}/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64 -fno-integrated-as -isystem $ENV{NDK}/platforms/android-${ANDROID_API}/arch-arm/usr/include" RT_CFLAGS)
+            endif()
+            if (LD_FLAGS_UNCONFIGURED AND NOT CMAKE_SYSTEM_PROCESSOR MATCHES "arm")
+                append("--sysroot=$ENV{NDK}/platforms/android-${ANDROID_API}/arch-arm -gcc-toolchain $ENV{NDK}/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64 -fuse-ld=bfd" LD_FLAGS)
+            endif()
+        endif()
+    endif()
 endif()
 
 if("${TARGET_SYSTEM}" MATCHES "UNIX")