patch 8.0.0004

Problem:    A string argument for function() that is not a function name
            results in an error message with NULL. (Christian Brabandt)
Solution:   Use the argument for the error message.

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4,
 /**/
     3,
 /**/