Aside from being C and "lightweight" I wonder when you'd want to pick this instead of POCO or ACE...
Not sure if climbing this high on HN on a U.S. holiday indicates a real need or clever marketing for this new project, but congratulations to them for getting the word out. Thanks also to you for sharing a couple well-established alternatives.
A few more (particularly nspr and apr): http://www.shlomifish.org/open-source/portability-libs/