This is populated by the clangd language service provider.
Also ignore the cmake-variants.yaml file.
This can be created locally to select various build/test configurations.
Fixes#4266
This is part (hopefully all) of the fixes for #776. The top-level
configure.ac configures googletest first and then googlemock.
With this changes it is possible to embed googletest into another
project that uses autoconf. For an example (though it is WIP), see
the commits (and soon PR) referenced from google/protobuf#236.
