Use x86_64-elf-gcc under MacOS

.github/workflows/macos.yml

@@ -18,11 +18,6 @@ jobs:
     build:
         name: Build
         runs-on: macos-latest
-        # Set environment variables
-        env:
-            # We globally set CC and CXX.
-            CC: x86_64-elf-gcc
-            CXX: x86_64-elf-g++
         steps:
             - name: Clone repository
               uses: actions/checkout@v3

CMakeLists.txt

@@ -31,6 +31,8 @@ message(STATUS "Kernel version : ${CMAKE_SYSTEM_VERSION}")
 if((${CMAKE_HOST_SYSTEM_NAME} STREQUAL "Darwin") OR APPLE)
     # Specify the linker flags.
     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -nostdlib")
+    set(CMAKE_C_COMPILER /usr/local/bin/x86_64-elf-gcc)
+    set(CMAKE_CXX_COMPILER /usr/local/bin/x86_64-elf-g++)
 elseif((${CMAKE_HOST_SYSTEM_NAME} STREQUAL "Windows") OR WIN32)
   # Windows set(EMULATOR_FLAGS ${EMULATOR_FLAGS} -sdl)
 else()