Issue a message or a warning when project isn't built because of .sln configurations #1935
Description
If the .sln file doesn't include a project file listed with the configuration being built, the project is silently excluded from building.
I thought it would be nice to at least issue a message that the .csproj listed in the file wasn't built because a list of configs for this project's GUID doesn't mention the current configuration.
As far as I can tell right now there's no message or warning at all.