I wrote:
> A little bit of googling suggests that this is a bug or incompatibility
> with openbsd's m4 (a tool that bison relies on):
> http://comments.gmane.org/gmane.comp.parsers.bison.bugs/2708
Scratch that: closer reading of the page says that the complainant was not
using some openbsd-specific copy of m4, but GNU m4 1.4.4, and that the
problem is not reproducible with newer versions of m4. So what it seems
to boil down to is "get a newer m4". Especially if you've got 1.4.4.
regards, tom lane
