Fix mac clang version

Author: Changqing-JING

.github/workflows/main.yml

@@ -438,16 +438,29 @@ jobs:
           export HOMEBREW_NO_AUTO_UPDATE=1
           brew install cmake googletest wabt llvm
           echo "/opt/homebrew/opt/llvm/bin" >> $GITHUB_PATH
+      - name: Determine clang compiler
+        run: |
+          set -ex
+          # Check if Xcode clang is available first, otherwise use Homebrew LLVM clang
+          if [ -x "/usr/bin/clang" ] && [ -x "/usr/bin/clang++" ]; then
+            echo "Using Xcode clang"
+            echo "CLANG_CC=/usr/bin/clang" >> $GITHUB_ENV
+            echo "CLANG_CXX=/usr/bin/clang++" >> $GITHUB_ENV
+          else
+            echo "Xcode clang not found, using Homebrew LLVM clang"
+            echo "CLANG_CC=clang" >> $GITHUB_ENV
+            echo "CLANG_CXX=clang++" >> $GITHUB_ENV
+          fi
       - name: Build and test
         run: |
           set -ex
           mkdir build
           cd build
-          cmake .. -DVB_ENABLE_DEV_FEATURE=OFF -DENABLE_CLANG_TIDY=1 -DENABLE_WERROR=1 -DENABLE_SPECTEST=1 -DTEST_VARIANTS=1 -DCMAKE_BUILD_TYPE:STRING=Debug -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_C_COMPILER=clang -DENABLE_UNITTEST=1 -DENABLE_DIS=1
+          cmake .. -DVB_ENABLE_DEV_FEATURE=OFF -DENABLE_CLANG_TIDY=1 -DENABLE_WERROR=1 -DENABLE_SPECTEST=1 -DTEST_VARIANTS=1 -DCMAKE_BUILD_TYPE:STRING=Debug -DCMAKE_CXX_COMPILER=$CLANG_CXX -DCMAKE_C_COMPILER=$CLANG_CC -DENABLE_UNITTEST=1 -DENABLE_DIS=1
           make -j $(sysctl -n hw.physicalcpu)
           make test
           rm -rf *
-          cmake .. -DVB_ENABLE_DEV_FEATURE=OFF -DENABLE_WERROR=1 -DENABLE_SPECTEST=1 -DTEST_VARIANTS=1 -DCMAKE_BUILD_TYPE:STRING=Release -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_C_COMPILER=clang -DENABLE_UNITTEST=1
+          cmake .. -DVB_ENABLE_DEV_FEATURE=OFF -DENABLE_WERROR=1 -DENABLE_SPECTEST=1 -DTEST_VARIANTS=1 -DCMAKE_BUILD_TYPE:STRING=Release -DCMAKE_CXX_COMPILER=$CLANG_CXX -DCMAKE_C_COMPILER=$CLANG_CC -DENABLE_UNITTEST=1
           make -j $(sysctl -n hw.physicalcpu)
           make test