I've run into problems here and there because of packages not setting
USE_BUILDLINK3=YES, even in the cases where they include no bl3 files
directly.  There's useful logic in there even for packages not using bl3
files, and I believe it's time to make it the global default and stop
fiddling with whether or not to turn it on.

Moreso, I also think we should drop NO_BUILDLINK and NO_TOOLS, merging them
into NO_BUILD.  If a build will be done, then bl3 and tool wrappering should
happen.  (If a compiler is not required, USE_LANGUAGES can be set to empty.)

Thoughts?

-- 
-- Todd Vierling <tv@duh.org> <tv@pobox.com>