Don't specify clang++ directly for manylinux

.github/workflows/build_cibuildwheel.yml

@@ -28,7 +28,6 @@ jobs:
           CIBW_ARCHS: auto64
           CIBW_ARCHS_MACOS: universal2
           CIBW_ENVIRONMENT_MACOS: MACOSX_DEPLOYMENT_TARGET=10.15
-          CIBW_ENVIRONMENT_LINUX: CXX=clang++
 
       - uses: actions/upload-artifact@v2
         with:

.github/workflows/pyproject.toml

 [[tool.cibuildwheel.overrides]]
 select = "*-musllinux*"
-before-all = "apk add clang"
\ No newline at end of file
+before-all = "apk add clang"
+environment = {"CXX=c++"}