patch 8.0.0243: tolower() does not work if the byte count changes

Problem:    When making a character lower case with tolower() changes the byte
            cound, it is not made lower case.
Solution:   Add strlow_save(). (Dominique Pelle, closes #1406)
diff --git a/src/version.c b/src/version.c
index df3ff07..d86705f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    243,
+/**/
     242,
 /**/
     241,