I was able to successfully build Allegro 4.2.2 and all of its components and demo programs with this version, but am unable to build it with TDM's latest build of 4.2.1.
Here is my post on the issue: http://forums.codeblocks.org/index.php/topic,6512.msg50658.html#msg50658
So, all in all, a good sign, I think.