patch 8.1.2119: memory access error for empty string

Problem:    memory access error for empty string when 'encoding' is a single
            byte encoding.
Solution:   Check for empty string when getting the length. (Dominique Pelle,
            closes #5021, closes #5007)
diff --git a/src/version.c b/src/version.c
index 0fa8440..edbd0a7 100644
--- a/src/version.c
+++ b/src/version.c
@@ -754,6 +754,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2119,
+/**/
     2118,
 /**/
     2117,