Now that some upstream code (see: ghostscript-gpl) is distributing code in tar.xz format and various other bits of Gentoo (logrotate, man / man-pages) support or can easily be made to support xz / xz-utils, adding support to Portage seems sensible and should require minimal effort. Reproducible: Always Steps to Reproduce:
It supports it, but you need to set EAPI=3 at the top of the ebuild. *** This bug has been marked as a duplicate of bug 273638 ***