nat: sizeof char *  != sizeof char[], make the code work on 64bit systems

The test cases were failing on 64bit systems because the sizeof
code operated on the pointer size which is 8 and longer than the
size that was intended to be used for comparing it.
diff --git a/debian/changelog b/debian/changelog
index 101e2c4..608867d 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+openbsc (0.12.0+git26-7) unstable; urgency=low
+
+  * 64bit fix for the MGCP rewriting
+
+ -- Holger Hans Peter Freyther <holger@freyther.de>  Wed, 07 Nov 2012 11:39:34 +0100
+
 openbsc (0.12.0+git26-6) precise; urgency=low
 
   * Added init script for osmocom-sgsn.