patch 8.0.0321: errors when trying to use scripts in tiny version

Problem:    When using the tiny version trying to load the matchit plugin
            gives an error. On MS-Windows some default mappings fail.
Solution:   Add a check if the command used is available. (Christian Brabandt)

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    321,
 /**/
     320,
 /**/