add excluded version exmaple

diff --git a/Zend/acinclude.m4 b/Zend/acinclude.m4
index 11cdbf7aea239580c7b253cd06bf0c588caccb6b..cec832fccb9fe4847c0c663aaedbdaee4109d65f 100644 (file)
--- a/Zend/acinclude.m4
+++ b/Zend/acinclude.m4
@@ -5,6 +5,7 @@ dnl This file contains local autoconf functions.
 AC_DEFUN([LIBZEND_BISON_CHECK],[
   # we only support certain bison versions, min: 2.4
   bison_version_min="204"
+  # non-working versions, e.g. "3.0 3.2"
   bison_version_exclude=""
 
   # for standalone build of Zend Engine