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.