Bison: A bit more verbose error messages in config.

aclocal.m4

@@ -151,9 +151,11 @@ AC_DEFUN([BIRD_CHECK_BISON_VERSION],
       ;;
     2.*)
       bird_bison_synclines=no
+      bird_bison_enhanced_error=no
       ;;
     3.* | 4.* | 5.* | 6.* | 7.* | 8.* | 9.*)
       bird_bison_synclines=yes
+      bird_bison_enhanced_error=yes
       ;;
     *)
       AC_MSG_ERROR([Couldn't parse Bison version $$1. Call the developers for help.])

conf/Makefile

@@ -12,7 +12,7 @@ BISON_DEBUG=-t
 endif
 
 cf-parse.tab.c: cf-parse.y
-	$(BISON) -bcf-parse -dv -pcf_ $(BISON_DEBUG) cf-parse.y
+	$(BISON) $(BISONFLAGS) -bcf-parse -dv -pcf_ $(BISON_DEBUG) cf-parse.y
 
 cf-parse.y: $(conf-fragments) $(conf-src)/gen_parser.m4
 	$(M4) $(M4FLAGS) -P $(conf-src)/gen_parser.m4 $(conf-fragments) >cf-parse.y

configure.ac

@@ -185,7 +185,12 @@ if test "$bird_bison_synclines" = yes; then
   M4FLAGS="$M4FLAGS -s"
 fi
 
+if test "$bird_bison_enhanced_error" = yes; then
+  BISONFLAGS="$BISONFLAGS -Dparse.lac=full -Dparse.error=verbose"
+fi
+
 AC_SUBST([M4FLAGS])
+AC_SUBST([BISONFLAGS])
 
 BIRD_CHECK_PROG_FLAVOR_GNU([$M4],
   [],

tools/Rules.in

@@ -23,6 +23,7 @@ CPPFLAGS=-I$(root-rel) -I$(srcdir) @CPPFLAGS@
 CFLAGS=$(CPPFLAGS) @CFLAGS@
 LDFLAGS=@LDFLAGS@
 M4FLAGS=@M4FLAGS@
+BISONFLAGS=@BISONFLAGS@
 LIBS=@LIBS@
 CLIENT_LIBS=@CLIENT_LIBS@
 CC=@CC@