C++11/C++14 testing can only do headers

Author: walbourn

.github/workflows/wslcxx.yml

@@ -56,34 +56,35 @@ jobs:
       working-directory: ${{ github.workspace }}
       run: rm -rf out
 
+    # Test suite requires C++17 features on Linux, so we only test the headers for C++11/C++14
     - name: 'Configure CMake (C++11)'
-      working-directory: ${{ github.workspace }}/Tests
+      working-directory: ${{ github.workspace }}/Tests/headertest
       run: cmake --preset=${{ matrix.build_type }} -DBUILD_CXX11=ON
       env:
         CC: gcc-${{ matrix.gcc }}
         CXX: g++-${{ matrix.gcc }}
 
     - name: 'Build (C++11)'
-      working-directory: ${{ github.workspace }}/Tests
+      working-directory: ${{ github.workspace }}/Tests/headertest
       run: cmake --build out/build/${{ matrix.build_type }}
 
     - name: 'Clean up'
-      working-directory: ${{ github.workspace }}
+      working-directory: ${{ github.workspace }}/Tests/headertest
       run: rm -rf out
 
     - name: 'Configure CMake (C++14)'
-      working-directory: ${{ github.workspace }}/Tests
+      working-directory: ${{ github.workspace }}/Tests/headertest
       run: cmake --preset=${{ matrix.build_type }} -DBUILD_CXX14=ON
       env:
         CC: gcc-${{ matrix.gcc }}
         CXX: g++-${{ matrix.gcc }}
 
     - name: 'Build (C++14)'
-      working-directory: ${{ github.workspace }}/Tests
+      working-directory: ${{ github.workspace }}/Tests/headertest
       run: cmake --build out/build/${{ matrix.build_type }}
 
     - name: 'Clean up'
-      working-directory: ${{ github.workspace }}
+      working-directory: ${{ github.workspace }}/Tests/headertest
       run: rm -rf out
 
     - name: 'Configure CMake (C++20)'