gecko-dev/build/build-clang/macosx64.json

{
    "target": "x86_64-apple-darwin",
    "cc": "{MOZ_FETCHES_DIR}/clang/bin/clang",
    "cxx": "{MOZ_FETCHES_DIR}/clang/bin/clang++",
    "as": "{MOZ_FETCHES_DIR}/clang/bin/clang",
    "ar": "{MOZ_FETCHES_DIR}/clang/bin/llvm-ar",
    "ranlib": "{MOZ_FETCHES_DIR}/clang/bin/llvm-ranlib",
    "libtool": "{MOZ_FETCHES_DIR}/clang/bin/llvm-libtool-darwin",
    "ld": "{MOZ_FETCHES_DIR}/clang/bin/clang"
}