YACC as bison -y. In this way, we ensure that bison is being used, but
the Makefiles have macros for using bison itself and for getting bison to
act like it is traditional yacc.
llvm-svn: 10774
do the following:
% cd llvm/autoconf
% aclocal
% autoconf -o ../configure
This changes facilitaties the following:
1) It should be easier to incorporate new autoconf macros.
2) It allows for conversion to Automake (should we ever desire it).
llvm-svn: 10655
