Change configure check to use $YACC, per Tom.

configure

@@ -4426,7 +4426,7 @@ done
 
 
 if test "$YACC"; then
-  if bison --version | sed q | $AWK '{ if ($4 < 1.875) exit 0; else exit 1;}'; then
+  if "$YACC" --version | sed q | $AWK '{ if ($4 < 1.875) exit 0; else exit 1;}'; then
     { echo "$as_me:$LINENO: WARNING:
 *** The installed version of Bison is too old.  PostgreSQL needs
 *** Bison version 1.875 or later." >&5

configure.in

 dnl Process this file with autoconf to produce a configure script.
-dnl $Header: /cvsroot/pgsql/configure.in,v 1.255 2003/06/06 19:11:55 momjian Exp $
+dnl $Header: /cvsroot/pgsql/configure.in,v 1.256 2003/06/07 16:32:05 momjian Exp $
 dnl
 dnl Developers, please strive to achieve this order:
 dnl
@@ -587,7 +587,7 @@ PGAC_CHECK_STRIP
 AC_CHECK_PROGS(YACC, ['bison -y'])
 
 if test "$YACC"; then
-  if bison --version | sed q | $AWK '{ if ($4 < 1.875) exit 0; else exit 1;}'; then
+  if "$YACC" --version | sed q | $AWK '{ if ($4 < 1.875) exit 0; else exit 1;}'; then
     AC_MSG_WARN([
 *** The installed version of Bison is too old.  PostgreSQL needs
 *** Bison version 1.875 or later.])