Only look for bison as YACC; other yaccs need to be selected explicitly.

When no suitable YACC is configured, supply useful informational messages
to users.  (Same way flex has been handled for a while.)

config/missing

@@ -5,16 +5,16 @@
 # behavior when certain utility programs are missing.
 
 case $1 in
-    flex)
-        # `missing flex <input> <output>'
+    flex|bison)
+        # `missing flex|bison <input> <output>'
         input=$2
         output=$3
         if test -f "$output"; then
             echo "\
 ***
-WARNING: \`flex' is missing on your system. You should only need it
+WARNING: \`$1' is missing on your system. You should only need it
 if you changed the file \`$input'; these changes will not take effect.
-You can get flex from a GNU mirror site.
+You can get $1 from a GNU mirror site.
 ***"
             echo "touch $output"
             touch "$output"
@@ -22,10 +22,10 @@ You can get flex from a GNU mirror site.
         else # ! test -f $output
             echo "\
 ***
-ERROR: \`flex' is missing on your system. It is needed to create the
-file \`$output'. You can either get flex from a GNU mirror site
+ERROR: \`$1' is missing on your system. It is needed to create the
+file \`$output'. You can either get $1 from a GNU mirror site
 or download an official distribution of PostgreSQL, which contains
-pre-packaged flex output.
+pre-packaged $1 output.
 ***"
             exit 1
         fi

config/programs.m4

-# $Header: /cvsroot/pgsql/config/programs.m4,v 1.3 2001/02/06 19:20:16 petere Exp $
+# $Header: /cvsroot/pgsql/config/programs.m4,v 1.4 2001/02/10 22:31:42 petere Exp $
 
 
 # PGAC_PATH_FLEX
@@ -46,19 +46,16 @@ fi
 if test x"$pgac_cv_path_flex" = x"no"; then
   if test -n "$pgac_broken_flex"; then
     AC_MSG_WARN([
-***
-The Flex version 2.5.3 you have at $pgac_broken_flex contains a bug. You
-should get version 2.5.4 or later.
-###])
+*** The Flex version 2.5.3 you have at $pgac_broken_flex contains a bug. You
+*** should get version 2.5.4 or later.])
   fi
 
   AC_MSG_WARN([
-***
-Without Flex you won't be able to build PostgreSQL from scratch, or change
-any of the scanner definition files. You can obtain Flex from a GNU mirror
-site. (If you are using the official distribution of PostgreSQL then you
-do not need to worry about this because the lexer files are pre-generated.)
-***])
+*** Without Flex you will not be able to build PostgreSQL from CVS or
+*** change any of the scanner definition files.  You can obtain Flex from
+*** a GNU mirror site.  (If you are using the official distribution of
+*** PostgreSQL then you do not need to worry about this because the Flex
+*** output is pre-generated.)])
 fi
 
 if test x"$pgac_cv_path_flex" = x"no"; then

configure.in

@@ -641,8 +641,20 @@ AC_PROG_RANLIB
 AC_CHECK_PROGS(LORDER, lorder)
 AC_PATH_PROG(TAR, tar)
 AC_CHECK_PROGS(PERL, perl)
-AC_PROG_YACC
+
+AC_CHECK_PROGS(YACC, ['bison -y'])
+if test -z "$YACC"; then
+  AC_MSG_WARN([
+*** Without Bison you will not be able to build PostgreSQL from CVS or
+*** change any of the parser definition files.  You can obtain Bison from
+*** a GNU mirror site.  (If you are using the official distribution of
+*** PostgreSQL then you do not need to worry about this because the Bison
+*** output is pre-generated.)  To use a different yacc program (possible,
+*** but not recommended), set the environment variable YACC before running
+*** 'configure'.])
+fi
 AC_SUBST(YFLAGS)
+
 if test "$with_tk" = yes; then
     AC_PATH_PROG(WISH, wish)
     test -z "$WISH" && AC_MSG_ERROR(['wish' is required for Tk support])

contrib/cube/Makefile

 #
-# $Header: /cvsroot/pgsql/contrib/cube/Makefile,v 1.1 2000/12/11 20:39:14 tgl Exp $
+# $Header: /cvsroot/pgsql/contrib/cube/Makefile,v 1.2 2001/02/10 22:31:42 petere Exp $
 #
 
 subdir = contrib/cube
@@ -25,9 +25,13 @@ include $(top_srcdir)/src/Makefile.shlib
 
 
 cubeparse.c cubeparse.h: cubeparse.y
+ifdef YACC
 	$(YACC) -d $(YFLAGS) -p cube_yy $<
 	mv -f y.tab.c cubeparse.c
 	mv -f y.tab.h cubeparse.h
+else
+	@$(missing) bison $< $@
+endif
 
 cubescan.c: cubescan.l
 ifdef FLEX

contrib/seg/Makefile

 #
-# $Header: /cvsroot/pgsql/contrib/seg/Makefile,v 1.1 2000/12/11 20:40:33 tgl Exp $
+# $Header: /cvsroot/pgsql/contrib/seg/Makefile,v 1.2 2001/02/10 22:31:42 petere Exp $
 #
 
 subdir = contrib/seg
@@ -25,9 +25,13 @@ include $(top_srcdir)/src/Makefile.shlib
 
 
 segparse.c segparse.h: segparse.y
+ifdef YACC
 	$(YACC) -d $(YFLAGS) -p seg_yy $<
 	mv -f y.tab.c segparse.c
 	mv -f y.tab.h segparse.h
+else
+	@$(missing) bison $< $@
+endif
 
 segscan.c: segscan.l
 ifdef FLEX

src/backend/bootstrap/Makefile

@@ -2,7 +2,7 @@
 #
 # Makefile for the bootstrap module
 #
-# $Header: /cvsroot/pgsql/src/backend/bootstrap/Makefile,v 1.26 2000/10/20 21:03:41 petere Exp $
+# $Header: /cvsroot/pgsql/src/backend/bootstrap/Makefile,v 1.27 2001/02/10 22:31:42 petere Exp $
 #
 #-------------------------------------------------------------------------
 
@@ -42,10 +42,14 @@ endef
 
 
 $(srcdir)/bootparse.c $(srcdir)/bootstrap_tokens.h: bootparse.y Makefile
+ifdef YACC
 	$(YACC) -d $(YFLAGS) $<
 	$(sed-magic) < y.tab.c > $(srcdir)/bootparse.c
 	$(sed-magic) < y.tab.h > $(srcdir)/bootstrap_tokens.h
 	rm -f y.tab.c y.tab.h
+else
+	@$(missing) bison $< $@
+endif
 
 $(srcdir)/bootscanner.c: bootscanner.l Makefile
 ifdef FLEX

src/backend/parser/Makefile

@@ -2,7 +2,7 @@
 #
 # Makefile for parser
 #
-# $Header: /cvsroot/pgsql/src/backend/parser/Makefile,v 1.31 2000/10/20 21:03:44 petere Exp $
+# $Header: /cvsroot/pgsql/src/backend/parser/Makefile,v 1.32 2001/02/10 22:31:42 petere Exp $
 #
 #-------------------------------------------------------------------------
 
@@ -25,9 +25,13 @@ SUBSYS.o: $(OBJS)
 	$(LD) $(LDREL) $(LDOUT) $@ $^
 
 $(srcdir)/gram.c $(srcdir)/parse.h: gram.y
+ifdef YACC
 	$(YACC) -d $(YFLAGS) $<
 	mv y.tab.c $(srcdir)/gram.c
 	mv y.tab.h $(srcdir)/parse.h
+else
+	@$(missing) bison $< $@
+endif
 
 $(srcdir)/scan.c: scan.l
 ifdef FLEX

src/interfaces/ecpg/preproc/Makefile

-# $Header: /cvsroot/pgsql/src/interfaces/ecpg/preproc/Makefile,v 1.72 2000/11/30 20:36:13 petere Exp $
+# $Header: /cvsroot/pgsql/src/interfaces/ecpg/preproc/Makefile,v 1.73 2001/02/10 22:31:42 petere Exp $
 
 subdir = src/interfaces/ecpg/preproc
 top_builddir = ../../../..
@@ -29,9 +29,13 @@ ecpg: $(OBJS)
 	$(CC) $(CFLAGS) $(LDFLAGS) $^ $(LIBS) -o $@
 
 $(srcdir)/preproc.c $(srcdir)/preproc.h: preproc.y
+ifdef YACC
 	$(YACC) -d $(YFLAGS) $<
 	mv y.tab.c $(srcdir)/preproc.c
 	mv y.tab.h $(srcdir)/preproc.h
+else
+	@$(missing) bison $< $@
+endif
 
 $(srcdir)/pgc.c: pgc.l
 ifdef FLEX

src/pl/plpgsql/src/Makefile

@@ -2,7 +2,7 @@
 #
 # Makefile for the plpgsql shared object
 #
-# $Header: /cvsroot/pgsql/src/pl/plpgsql/src/Makefile,v 1.10 2001/02/09 01:05:42 tgl Exp $
+# $Header: /cvsroot/pgsql/src/pl/plpgsql/src/Makefile,v 1.11 2001/02/10 22:31:42 petere Exp $
 #
 #-------------------------------------------------------------------------
 
@@ -55,10 +55,14 @@ pl_parse.o: $(srcdir)/pl_gram.c $(srcdir)/pl_scan.c plpgsql.h
 # they must be generated in the srcdir (as opposed to builddir).
 
 $(srcdir)/pl_gram.c $(srcdir)/pl.tab.h: gram.y
+ifdef YACC
 	$(YACC) -d $(YFLAGS) $<
 	sed -e 's/yy/plpgsql_yy/g' -e 's/YY/PLPGSQL_YY/g' < y.tab.c > $(srcdir)/pl_gram.c
 	sed -e 's/yy/plpgsql_yy/g' -e 's/YY/PLPGSQL_YY/g' < y.tab.h > $(srcdir)/pl.tab.h
 	rm -f y.tab.c y.tab.h
+else
+	@$(missing) bison $< $@
+endif
 
 $(srcdir)/pl_scan.c: scan.l
 ifdef FLEX