patch 7.4.890

Problem:    Build failure when using dynamic python but not python3.
Solution:   Adjust the #if to also include DYNAMIC_PYTHON3 and UNIX.

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    890,
 /**/
     889,
 /**/