drop compatibility with Yacc, Bison < 3 in HTML parser

This does not change build requirements, as other parsers already require Bison
3. Related to #1806.

diff --git a/lib/common/htmlparse.y b/lib/common/htmlparse.y
index 6e92deeb7e053af7d2a7469a976a9290d234f701..0e07cf6a1cc9dd47c79e064de90c348e1e3e5f2e 100644 (file)
--- a/lib/common/htmlparse.y
+++ b/lib/common/htmlparse.y
@@ -11,6 +11,8 @@
  * Contributors: See CVS logs. Details at http://www.graphviz.org/
  *************************************************************************/
 
+%require "3.0"
+
 %{
 
 #include <common/render.h>