fix macos build

Author: 0xGeorgii

.github/workflows/build-llvm-artifacts.yml

@@ -74,7 +74,7 @@ jobs:
               -DCMAKE_INSTALL_PREFIX="${{ github.workspace }}/llvm-install" \
               ../llvm
           elif [ "$RUNNER_OS" == "macOS" ]; then
-            # Set SDKROOT to ensure CMake's try_compile checks find system headers
+            # Set SDKROOT and pass it to CMake to ensure it finds system headers
             export SDKROOT=$(xcrun --show-sdk-path)
             cmake -G Ninja \
               -DCMAKE_BUILD_TYPE=Release \
@@ -92,6 +92,7 @@ jobs:
               -DLLVM_TOOL_LLVM_CONFIG_BUILD=ON \
               -DHAVE_CXX_ATOMICS_WITHOUT_LIB=ON \
               -DHAVE_CXX_ATOMICS64_WITHOUT_LIB=ON \
+              -DDEFAULT_SYSROOT="$SDKROOT" \
               -DCMAKE_INSTALL_PREFIX="${{ github.workspace }}/llvm-install" \
               ../llvm
           else