patch 7.4.1437

Problem:    Old system doesn't have isinf() and NAN. (Ben Fritz)
Solution:   Adjust #ifdefs.  Detect isnan() and isinf() functions with
            configure. Use a replacement when missing. (Kazunobu Kuriyama)

src/version.c

@@ -743,6 +743,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1437,
 /**/
     1436,
 /**/