PATCH: gengtype-yacc.y portability

[Loren James Rittle]

>> Attn: Geoff Keating

Thank you Geoff for the quick review (the FreeBSD system guys have an
aversion to both bison and autoconf when it comes to their system
compiler configuration.)

>> I verified that gentype output itself was the same before and after
>> this patch.

> This is OK.  (Please check the status of the 3.3 branch before
> committing it there, though.)

Committed to mainline.  Pulled onto 3.3 branch working tree.
Reverified the zero change property in generated gtype-* files.
Committed to the 3.3 branch.  Closed the PR.  Thank you for the report
Alex. - Loren