patch 9.1.0957: MS-Windows: conversion warnings

Problem:  MS-Windows: conversion warnings
Solution: add explicit type casts (Yegappan Lakshmanan)

closes: #16288

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/viminfo.c b/src/viminfo.c
index 0a433a7..5f1ad74 100644
--- a/src/viminfo.c
+++ b/src/viminfo.c
@@ -1142,7 +1142,7 @@
 			// freed later, also need to free "buf" later
 			value->bv_tofree = buf;
 		    s = sconv;
-		    len = STRLEN(s);
+		    len = (int)STRLEN(s);
 		    converted = TRUE;
 		}
 	    }