* tool/ytab.sed: `p` is too short to distinguish alone from other
names. fix for more old bison which does not support %lex-param
at yydestruct. add `p` argument to non-prototype declaration of
yy_stack_print.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61826 b2dd03c8-39d4-4d8f-98ff-823fe69b080e