patch 7.4.1440

Problem:    Can't build on Windows.
Solution:   Change #ifdefs.  Only define isnan when used.

src/version.c

@@ -743,6 +743,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1440,
 /**/
     1439,
 /**/