updated for version 7.3.555

Problem:    Building on IBM z/OS fails.
Solution:   Adjust configure. Use the QUOTESED value from config.mk instead of
            the hard coded one in Makefile. (Stephen Bovy)

src/version.c

@@ -714,6 +714,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    555,
 /**/
     554,
 /**/