I had a project I worked on where I couldn’t debug my Application with Xcode 4.5 because there was a conflict between the libTIFF I was using in one of my modules and the copy of libTIFF included with the ImageIO framework.
It turns out that the two libTIFF libraries were actually different, so, for the small test project I created, I decided to statically link in the code I needed from libTIFF so that dlopen wouldn’t supplant the copy of libTIFF ImageIO needed with my copy.
References:
http://lists.apple.com/archives/xcode-users/2008/Jan/msg00019.html
http://lists.apple.com/archives/x11-users/2007/Mar/msg00003.html