Description of problem:
Firefox won't build using mock.
Version-Release number of selected component (if applicable):
Adding libXt-devel to BuildRequires allows it to build.
Created attachment 124347 [details]
Partial build log
This issue has been fixed, an excerpt from firefox.spec:
* Tue Feb 28 2006 Karsten Hopp <email@example.com>
- add buildrequires libXt-devel for X11/Intrinsic.h, X11/Shell.h