patch 7.4.845
Problem:    Compiler warning for possible loss of data.
Solution:   Add a type cast. (Erich Ritz)
diff --git a/src/misc1.c b/src/misc1.c
index ee2da08..8b5ea64 100644
--- a/src/misc1.c
+++ b/src/misc1.c
@@ -3985,7 +3985,7 @@
 		len = dstlen;
 	    vim_strncpy(dst, var, len);
 	    dst += len;
-	    dstlen -= len;
+	    dstlen -= (int)len;
 	    continue;
 	}
 #endif