drop compatibility with Yacc, Bison < 3 in gml parser

Other parsers in the tree, e.g. lib/cgraph/grammar.y, already require Bison 3+,
so this does not change build requirements. Related to #1806.

diff --git a/cmd/tools/gmlparse.y b/cmd/tools/gmlparse.y
index 47644d705e4276765050649be619454ea5990eb1..b3dd1b899d7a8f3b85767f8eb2edb7ad3edd8caa 100644 (file)
--- a/cmd/tools/gmlparse.y
+++ b/cmd/tools/gmlparse.y
@@ -11,6 +11,8 @@
  * Contributors: See CVS logs. Details at http://www.graphviz.org/
  *************************************************************************/
 
+%require "3.0"
+
 %{
 #include <stdlib.h>
 #include <stddef.h>