Test which images need the cmake to force the protobuf language version.

Author: thomasvl

.github/workflows/build.yml

@@ -34,6 +34,7 @@ jobs:
           hook: "SWIFT_BUILD_TEST_HOOK=\"-Xswiftc -warnings-as-errors\""
         - version: 5.8.1-focal
           hook: "SWIFT_BUILD_TEST_HOOK=\"-Xswiftc -warnings-as-errors\""
+          cmake_extra: "-DCMAKE_CXX_STANDARD=17"
         # protobuf_git can reference a commit, tag, or branch
         # commit: "commits/6935eae45c99926a000ecbef0be20dfd3d159e71"
         # tag: "ref/tags/v3.11.4"
@@ -92,7 +93,7 @@ jobs:
         mkdir cmake_build
         cd cmake_build
         cmake \
-          -DCMAKE_CXX_STANDARD=17 \
+          ${{ matrix.swift.cmake_extra }} \
           -DCMAKE_BUILD_TYPE=Release \
           -Dprotobuf_BUILD_TESTS=OFF \
           -Dprotobuf_INSTALL=OFF \