Fix GHA CI Windows Path Limits (#451)

GHA Windows runners have an enviornment option LongPathsEnabled which defaults to true (1).

This can be tested by running (Get-ItemProperty "HKLM:System\CurrentControlSet\Control\FileSystem").LongPathsEnabled in a Windows runner.

This value isn't honored within bash shells on Windows and the path limit caused build errors in the Packaging Build workflow for Firestore targets.

This change removes 'bash' as the shell when building and instead executespython scripts/gha/build_desktop.py via the host operating system's default shell.

Author: DellaBitta

.github/workflows/cpp-packaging.yml

@@ -339,15 +339,23 @@ jobs:
         run: |
           python scripts/gha/install_prereqs_desktop.py
 
-      - name: Build desktop SDK
+      - name: Export verbose flag
         shell: bash
         run: |
           verbose_flag=
           if [[ -n "${{ github.event.inputs.verboseBuild }}" && "${{ github.event.inputs.verboseBuild }}" -ne 0 ]]; then
             verbose_flag=--verbose
           fi
-          python scripts/gha/build_desktop.py --arch "${{ matrix.architecture }}" --config "${{ matrix.build_type }}" --msvc_runtime_library "${{ matrix.msvc_runtime }}" --linux_abi "${{ matrix.linux_abi }}" --build_dir out-sdk ${verbose_flag} ${{ matrix.additional_build_flags }}
-          # Make a list of all the source files, for debugging purposes.
+          echo "VERBOSE_FLAG=${verbose_flag}" >> $GITHUB_ENV
+      
+      # Run the build in the host OS default shell since Windows can't handle long path names in bash.
+      - name: Build desktop SDK
+        run: |
+          python scripts/gha/build_desktop.py --arch "${{ matrix.architecture }}" --config "${{ matrix.build_type }}" --msvc_runtime_library "${{ matrix.msvc_runtime }}" --linux_abi "${{ matrix.linux_abi }}" --build_dir out-sdk ${VERBOSE_FLAG} ${{ matrix.additional_build_flags }}
+
+      - name: Archive SDK
+        shell: bash
+        run: |
           cd out-sdk
           find .. -type f -print > src_file_list.txt
           tar -czhf ../firebase-cpp-sdk-${{ env.SDK_NAME }}-build.tgz .