Re-apply r359267 now that tools are using the proper include path

Original commit message:
bsd.lib.mk: Do not include bsd.incs.mk for INTERNALLIB

f we're building an internal lib do not bother including bsd.incs.mk so we
will not install the headers.
This also "solves" a problem with pkgbase where a libXXX-development package
is created and due to how packages are created we add a dependency to a
libXXX package that doesn't exists.