So far, as Bakul pointed out, only %error-verbose (from memory) stands outin my most recent changes, but there are other reasons and, unfortunately,GNU Bison uses its own extensions to bootstrap, which is where I maywell be getting even more muddled up.
Is your goal to a) have the standard go distribution build on plan9 with no changes or b) do a minimal infrastructure to make future ports easy or c) do a one time port?
If it is c), why not just use the 9front port? If b) or a), why not look at what they have done at the very least?
I'd first fix Make.* to use byacc, or even better, p9p yacc, and run all the tests on a bsd and just fix %error-verbose. If they pass, no need to port bison or may be even byacc.