Install yacc with a link as byacc (and the man page). Some gnu autoconf

scripts that check for features/fixes in bison also check for byacc and
dont find it unless there is a 'byacc' in the path.

usr.bin/yacc/Makefile

@@ -4,6 +4,8 @@ PROG=	yacc
 SRCS=	closure.c error.c lalr.c lr0.c main.c mkpar.c output.c reader.c \
 	skeleton.c symtab.c verbose.c warshall.c
 MAN1=	yacc.1 yyfix.1
+LINKS+=	${BINDIR}/yacc ${BINDIR}/byacc
+MLINKS+=yacc.1 byacc.1
 
 beforeinstall:
 	${INSTALL} -c -o ${BINOWN} -g ${BINGRP} -m ${BINMODE} \