Backed out changeset 984c21a8cf6a (bug 1744890) for causing build bustages. CLOSED TREE

build/build-clang/clang-13-macosx64.json

@@ -12,6 +12,7 @@
     "wasi-compiler-rt": "{MOZ_FETCHES_DIR}/compiler-rt",
     "patches": [
       "static-llvm-symbolizer_clang_12.patch",
+      "compiler-rt-cross-compile.patch",
       "revert-llvmorg-13-init-7827-g2a078c307204.patch",
       "revert-llvmorg-13-init-8182-gc2297544c047.patch",
       "llvmorg-14-init-2833-gbadcd5858972.patch",

build/build-clang/clang-tidy-macosx64.json

@@ -11,6 +11,7 @@
     "ld": "{MOZ_FETCHES_DIR}/clang/bin/clang",
     "patches": [
       "clang-tidy-ci.patch",
+      "compiler-rt-cross-compile.patch",
       "compiler-rt-13-no-codesign.patch"
     ]
 }

build/build-clang/compiler-rt-cross-compile.patch

@@ -0,0 +1,15 @@
+Add `-target x86_64-apple-darwin' to the compiler-rt overridden CFLAGS
+
+diff --git a/compiler-rt/cmake/Modules/CompilerRTDarwinUtils.cmake b/compiler-rt/cmake/Modules/CompilerRTDarwinUtils.cmake
+index 28d398672..aac68bf36 100644
+--- a/compiler-rt/cmake/Modules/CompilerRTDarwinUtils.cmake
++++ b/compiler-rt/cmake/Modules/CompilerRTDarwinUtils.cmake
+@@ -265,7 +265,7 @@ endfunction()
+ macro(darwin_add_builtin_libraries)
+   set(DARWIN_EXCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/Darwin-excludes)
+ 
+-  set(CFLAGS "-fPIC -O3 -fvisibility=hidden -DVISIBILITY_HIDDEN -Wall -fomit-frame-pointer")
++  set(CFLAGS "-fPIC -O3 -fvisibility=hidden -DVISIBILITY_HIDDEN -Wall -fomit-frame-pointer -target ${LLVM_DEFAULT_TARGET_TRIPLE} -isysroot ${CMAKE_OSX_SYSROOT} -I${CMAKE_OSX_SYSROOT}/usr/include")
+   set(CMAKE_C_FLAGS "")
+   set(CMAKE_CXX_FLAGS "")
+   set(CMAKE_ASM_FLAGS "")