updated for version 7.4.498
Problem:    Typo in DOS makefile.
Solution:   Change exists to exist. (Ken Takata)
diff --git a/src/version.c b/src/version.c
index f0fd5a3..ae1a56b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -742,6 +742,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    498,
+/**/
     497,
 /**/
     496,