Workaround GitHub Actions build issue in Windows.

See actions/runner-images#6627

.github/workflows/main.yml

@@ -113,6 +113,13 @@ jobs:
       if: steps.vars.outputs.angle == '1'
       working-directory: angle
       run: 7z x angle-win-${{ steps.vars.outputs.arch }}.zip
+    - name: Delete Strawbery Perl
+      # https://github.com/actions/runner-images/issues/6627
+      # In particular, this is not pretty, but even CMAKE_IGNORE_PREFIX_PATH
+      # cannot help in this case. Delete the whole folder!
+      run: |
+        rmdir /s /q C:\Strawberry
+        exit /b 0
     - name: Configure
       run: cmake -Bbuild -Hmegasource -T v142 -A ${{ matrix.platform }} -DCMAKE_INSTALL_PREFIX=%CD%\install ${{ steps.vars.outputs.moredef }}
     - name: Install