GitLab

Making CompilerOptionsBuilder to use the toolchain from the project part
simplifies its public API, but following the code paths initiated by
ClangCodeModel and ClangStaticAnalyzer gets harder, so better enable the
separation of those by making CompilerOptionsBuilder a base class.

Change-Id: I0a6bb3f8323ba09b88135a7f9d1ef967331a8ff0
Reviewed-by: Christian Kandeler <christian.kandeler@theqtcompany.com>