patch 8.0.0199: compiler warnings for libcall

Problem:    Warning for an unused parameter when the libcall feature is
            disabled.  Warning for a function type cast when compiling with
            -pedantic.
Solution:   Add UNUSED.  Use a different type cast. (Damien Molinier)

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    199,
 /**/
     198,
 /**/