patch 9.1.0024: z/OS (MVS) support can be improved

Problem:  z/OS (MVS) support can be improved
Solution: set UTF-8 as the default encoding for z/OS

closes: #13821

Signed-off-by: Igor Todorovski <itodorov@ca.ibm.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/option.c b/src/option.c
index 2372c1a..14447f5 100644
--- a/src/option.c
+++ b/src/option.c
@@ -450,9 +450,10 @@
     char_u	*p;
     int		opt_idx;
 
-# ifdef MSWIN
+# if defined(MSWIN) || defined(__MVS__)
     // MS-Windows has builtin support for conversion to and from Unicode, using
     // "utf-8" for 'encoding' should work best for most users.
+    // z/OS built should default to UTF-8 mode as setlocale does not respect utf-8 environment variable locales
     p = vim_strsave((char_u *)ENC_DFLT);
 # else
     // enc_locale() will try to find the encoding of the current locale.
diff --git a/src/option.h b/src/option.h
index 646056b..0cf6a8c 100644
--- a/src/option.h
+++ b/src/option.h
@@ -130,7 +130,7 @@
 #define ENC_UCSBOM	"ucs-bom"	// check for BOM at start of file
 
 // default value for 'encoding'
-#ifdef MSWIN
+#if defined(MSWIN) || defined(__MVS__)
 # define ENC_DFLT	"utf-8"
 #else
 # define ENC_DFLT	"latin1"
diff --git a/src/version.c b/src/version.c
index 0099da5..5fba3de 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    24,
+/**/
     23,
 /**/
     22,