Make sure to pass C++ version to preprocessor as well.

Author: stefanseefeld

.github/workflows/test-osx.yml

@@ -36,6 +36,7 @@ jobs:
           --builddir=build \
           cxx.name=${{ matrix.cxx }} \
           cxxflags=-std=${{ matrix.std }} \
+          cppflags=-std=${{ matrix.std }} \
           -j`sysctl -n hw.ncpu`
     - name: test
       run: |
@@ -44,5 +45,6 @@ jobs:
           --builddir=build\
           cxx.name=${{ matrix.cxx }} \
           cxxflags=-std=${{ matrix.std }} \
+          cppflags=-std=${{ matrix.std }} \
           -j`sysctl -n hw.ncpu` \
           test.report

.github/workflows/test-ubuntu.yml

@@ -39,6 +39,7 @@ jobs:
           --builddir=build \
           cxx.name=${{ matrix.cxx }} \
           cxxflags=-std=${{ matrix.std }} \
+          cppflags=-std=${{ matrix.std }} \
           -j`nproc`
     - name: test
       run: |
@@ -47,5 +48,6 @@ jobs:
           --builddir=build \
           cxx.name=${{ matrix.cxx }} \
           cxxflags=-std=${{ matrix.std }} \
+          cppflags=-std=${{ matrix.std }} \
           -j`nproc` \
           test.report