chore: Update build-mysql-darwin.sh to support MySQL 8.0 or later

.github/build-mysql-darwin.sh

@@ -24,14 +24,16 @@ esac
 PREFIX=$RUNNER_TOOL_CACHE/mysql/$MYSQL_VERSION/$MYSQL_ARCH
 export LDFLAGS=-Wl,-rpath,$PREFIX/lib
 
-# install LLVM
-brew install llvm@17
-LLVM_PATH=$(brew --prefix llvm@17)
-export PATH="$LLVM_PATH/bin:$PATH"
-export LDFLAGS="$LDFLAGS -L$LLVM_PATH/lib"
-export CPPFLAGS="$CPPFLAGS -I$LLVM_PATH/include"
-export CC=$LLVM_PATH/bin/clang
-export CXX=$LLVM_PATH/bin/clang++
+if [[ "$MYSQL_VERSION" =~ ^[89][.] ]]; then # MySQL 8.0 or later
+    # install LLVM
+    brew install llvm@17
+    LLVM_PATH=$(brew --prefix llvm@17)
+    export PATH="$LLVM_PATH/bin:$PATH"
+    export LDFLAGS="$LDFLAGS -L$LLVM_PATH/lib"
+    export CPPFLAGS="$CPPFLAGS -I$LLVM_PATH/include"
+    export CC=$LLVM_PATH/bin/clang
+    export CXX=$LLVM_PATH/bin/clang++
+fi
 
 # detect the number of CPU Core
 JOBS=$(sysctl -n hw.logicalcpu_max)