Choose 64-bit MinGW version based on Qt versions

And get some CMake debugging to understand the 32-bit MinGW issue.

Author: pcolby

.github/workflows/build.yaml

@@ -471,7 +471,14 @@ jobs:
           - { toolchain: 'msvc',  generator: 'NMake Makefiles', dll: QtPokit.dll }
           # Optional additional tools to be installed by aqt (via install-qt-action).
           - { toolchain: 'mingw', arch: x86,    aqtTools: 'tools_mingw,qt.tools.win32_mingw810' }
-          - { toolchain: 'mingw', arch: x86-64, aqtTools: 'tools_mingw1310' }
+          # Use Qt-provided 64-bit MinGW for recent Qt's (defaulting to GitHub's 12.2.0 version for older Qt versions).
+          - { toolchain: 'mingw', arch: x86-64, qt: '5.14.2', aqtTools: 'tools_mingw1310' }
+          - { toolchain: 'mingw', arch: x86-64, qt: '5.15.2', aqtTools: 'tools_mingw1310' }
+          - { toolchain: 'mingw', arch: x86-64, qt: '6.4.3',  aqtTools: 'tools_mingw1310' }
+          - { toolchain: 'mingw', arch: x86-64, qt: '6.5.3',  aqtTools: 'tools_mingw1310' }
+          - { toolchain: 'mingw', arch: x86-64, qt: '6.6.3',  aqtTools: 'tools_mingw1310' }
+          - { toolchain: 'mingw', arch: x86-64, qt: '6.7.3',  aqtTools: 'tools_mingw1310' }
+          - { toolchain: 'mingw', arch: x86-64, qt: '6.8.3',  aqtTools: 'tools_mingw1310' }
     steps:
       - uses: actions/checkout@v4
       - name: Install host Qt for cross-compilation
@@ -527,6 +534,7 @@ jobs:
           cmake -D CMAKE_BUILD_TYPE=Release ^
                 -D QT_HOST_PATH=%qtHostPath% ^
                 -D QT_INSTALL_DOCS=%RUNNER_WORKSPACE%\Qt\Docs\Qt-${{ matrix.qt }} ^
+                --debug-output ^
                 -G "${{ matrix.generator }}" -S "%GITHUB_WORKSPACE%" -B "%RUNNER_TEMP%"
           cmake --build "%RUNNER_TEMP%"
       - name: Capture build-output variables