Commit Briefs
PowerPC Linux support from ericvh.
Mainly adding va_copy/va_end. Also fix bug in sprint wrapping around top of memory.
Clean up yacc files in mkcommon, mkhdr.
Add nan to lib9. Fix memory corruption bugs in 9term.
Add the #goo to allow use in C++.
Silence a few more warnings. Strip down the mkfiles more. Fix bug in X11 mouse handling, note groups.
Changes for Mac OS X. Most important is stack sizes in samterm,
which were completely bogus. (Libthread used to ignore them but not anymore. Maybe we really should ignore them, but that breaks Venti, which needs *really* big stacks.)