Update LLVM@18 to support C++20

.github/workflows/release.yml

@@ -70,9 +70,23 @@ jobs:
         conan config set "storage.path=$env:GITHUB_WORKSPACE/conan_data"
         conan install --build=openssl --install-folder conan_build .
 
-    - uses: pypa/cibuildwheel@v2.16.5
+    - name: Install llvm@18 and link asio on macOS
+      if: matrix.platform == 'macos'
+      run: |
+        brew install llvm@18
+        echo "$(brew --prefix)/opt/llvm/bin" >> $GITHUB_PATH
+        echo "LDFLAGS=-L$(brew --prefix)/opt/llvm/lib -L$(brew --prefix)/opt/llvm/lib/c++ -L/opt/homebrew/lib -Wl,-rpath,$(brew --prefix)/opt/llvm/lib/c++" >> "$GITHUB_ENV"
+        echo "CPPFLAGS=-I$(brew --prefix)/opt/llvm/include -I/opt/homebrew/include -fexperimental-library" >> "$GITHUB_ENV"
+        echo "CC=clang" >> "$GITHUB_ENV"
+        echo "CXX=clang++" >> "$GITHUB_ENV"
+        echo "OBJC=clang" >> "$GITHUB_ENV"
+        echo "CC_LD=lld" >> "$GITHUB_ENV"
+        echo "CXX_LD=lld" >> "$GITHUB_ENV"
+        echo "OBJC_LD=lld" >> "$GITHUB_ENV"
+        
+    - uses: pypa/cibuildwheel@v2.18.1
       env:
-        MACOSX_DEPLOYMENT_TARGET: 10.14
+        MACOSX_DEPLOYMENT_TARGET: 14
 
     - name: Verify clean directory
       run: git diff --exit-code