Merge pull request #4020 from Sonicadvance1/add_cross_compile_toolchain

CMake: Adds an AArch64 cross-compile toolchain file

CMakeToolchains/AArch64.cmake

@@ -0,0 +1,35 @@
+# This is a reference AArch64 cross compile script
+# Pass in to cmake when building:
+# eg: cmake -DCMAKE_TOOLCHAIN_FILE=../CMakeToolchains/AArch64.cmake ..
+if (NOT DEFINED ENV{SYSROOT})
+  message(FATAL_ERROR "Need to have SYSROOT environment variable set")
+endif()
+
+set(CMAKE_SYSTEM_NAME Linux)
+set(CMAKE_SYSTEM_PROCESSOR aarch64)
+set(CMAKE_CROSSCOMPILING TRUE)
+
+# Target triple needs to match the binutils exactly
+set(TARGET_TRIPLE aarch64-linux-gnu)
+set(CMAKE_C_COMPILER "clang")
+set(CMAKE_CXX_COMPILER "clang++")
+set(CMAKE_C_COMPILER_AR "llvm-ar")
+set(CMAKE_CXX_COMPILER_AR "llvm-ar")
+set(CMAKE_C_COMPILER_RANLIB "llvm-ranlib")
+set(CMAKE_CXX_COMPILER_RANLIB "llvm-ranlib")
+set(CMAKE_LINKER "ld.lld")
+
+set(CMAKE_C_COMPILER_TARGET ${TARGET_TRIPLE})
+set(CMAKE_CXX_COMPILER_TARGET ${TARGET_TRIPLE})
+
+# Set the environment variable SYSROOT to the aarch64 rootfs
+set(CMAKE_FIND_ROOT_PATH "$ENV{SYSROOT}")
+set(CMAKE_SYSROOT "$ENV{SYSROOT}")
+
+list(APPEND CMAKE_PREFIX_PATH "$ENV{SYSROOT}/usr/lib/${TARGET_TRIPLE}/cmake/")
+
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)