patch 9.1.0824: too many strlen() calls in register.c

Problem:  too many strlen() calls in register.c
Solution: refactor code, add string_T struct to keep track
          of string lengths (John Marriott)

closes: #15952

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 */
+/**/
+    824,
 /**/
     823,
 /**/