patch 9.1.0409: too many strlen() calls in the regexp engine

Problem:  too many strlen() calls in the regexp engine
Solution: refactor code to retrieve strlen differently, make use
          of bsearch() for getting the character class
          (John Marriott)

closes: #14648

Signed-off-by: John Marriott <basilisk@internode.on.net>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    409,
 /**/
     408,
 /**/