Bump dxcommon to get help output improvements.

As well as a nice size reduction on modern platforms, basically
everything is working on ULTRIX 4.5 now too, cool.

diff --git a/common b/common
index 9cacb902a5d6f6c4271ee3066e2efe13663f145a..cc589a8b1539e9515985081d9498dda2b6b6caf7 160000 (submodule)
--- a/common
+++ b/common
@@ -1 +1 @@
-Subproject commit 9cacb902a5d6f6c4271ee3066e2efe13663f145a
+Subproject commit cc589a8b1539e9515985081d9498dda2b6b6caf7