Due to the bug in bison 2.1, I always use version 1.875:
http://www.mail-archive.com/bug-bison(at)gnu(dot)org/msg00718.html
""Christopher Kings-Lynne"" <chris(dot)kingslynne(at)gmail(dot)com>
> What version of Bison is currently required to compile HEAD? 1.75
> doesn't seem to work...
>
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