Hi all,
I'd like to see a strong preference of
USE_LANGUAGES=	c c++
or depending on the package
USE_LANGUAGES=	c++
instead of using +=, esp. since the former can be used to mark packages
as not using C. I don't know if we ever want to make the annotation of C
usage mandatory, but listening them explicitly is IMO better style.

I don't think making it a warning is necessary a good idea, since e.g.
Makefile.common could specify C and the real Makefile add C++, but
that's a separate issue.

What do you think?

Joerg