Stop downloading LLVM on MacOS CI

.github/workflows/MacOS_Build.yml

@@ -23,13 +23,10 @@ jobs:
     - name: Fetch submodules
       run: git submodule update --init --recursive
 
-    - name: Install LLVM # MacOS comes with "AppleClang" instead of regular Clang, and it can't build the project because no proper C++20
-      run: brew install llvm
-
     - name: Configure CMake
       # Configure CMake in a 'build' subdirectory. `CMAKE_BUILD_TYPE` is only required if you are using a single-configuration generator such as make.
       # See https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html?highlight=cmake_build_type
-      run: cmake -B ${{github.workspace}}/build -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}} -DCMAKE_C_COMPILER=/usr/local/opt/llvm/bin/clang -DCMAKE_CXX_COMPILER=/usr/local/opt/llvm/bin/clang++
+      run: cmake -B ${{github.workspace}}/build -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}}
 
     - name: Build
       # Build your program with the given configuration