Doxygen 1.5.0 has been released.
Also 1.5.1 has been released today. I've succesfully emerged 1.5.1 using 1.4.7 ebuild and all gentoo patches from 1.4.7. I also generated a doc for a java project consisting of 100+ source files. No problems of any sort occurred.
doxygen 1.5.1 is now in ~arch.