patch 8.1.1858: test for multi-byte mapping fails on some systems

Problem:    Test for multi-byte mapping fails on some systems.
Solution:   Test in another way.
diff --git a/src/version.c b/src/version.c
index 5bd944d..ee4bb90 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1858,
+/**/
     1857,
 /**/
     1856,