Created attachment 333808 [details] inkscape-0.48.4:20121230-015256.log fails at configure phase
My log looks excactly the same for clang-3.4.1-r100, too.
I tried reproducing the error with inkscape-0.48.5, as .4 is not in tree anymore. With this version inkscape builds and tests fine. I checked the changelog, this has been fixed by removing the ancient GCC >= 3.0 check in the configure, which is the issue hit in the attached emerge log. I think this bug can be safely closed as RESOLVED UPSTREAM.