Query length string

I have gotten as far as the tcop, now I need some help as far as
yacc(bison?) goes.  Yacc seems to use an input buffer called YY_BUFFER or
something, which appears to be a fixed length string.  Does anybody have any
idea how I go about changing this so that I can pass a char * which I have
allocated (apart from reading the manual, I'm looking for the 'technical
summary' ;-)?

Sorry the front-end changes are taking so long to get out, I have been quite
busy.  I was also working on some outdated source, and spent a while
patching and diffing.  But they are working and ready to go.  Tomorrow...
maybe.....

MikeA