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.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"