Update GitHub Actions workflow to set CFLAGS and CXXFLAGS for specific architectures

Author: arnavch

.github/workflows/CI.yml

@@ -34,10 +34,11 @@ jobs:
       - uses: actions/setup-python@v5
         with:
           python-version: '3.10'
-      - name: Set CFLAGS for specific targets
+      - name: Set CFLAGS and CXXFLAGS for specific targets
         run: |
           if [[ ${{ matrix.platform.target }} == "ppc64le" || ${{ matrix.platform.target }} == "aarch64" || ${{ matrix.platform.target }} == "armv7" ]]; then
             echo "CFLAGS=-std=c99" >> $GITHUB_ENV
+            echo "CXXFLAGS=-std=c++11" >> $GITHUB_ENV
           fi
       - name: Build wheels
         uses: PyO3/maturin-action@v1