Repoman triggers dependency.missingslot on media-libs/libpng atom, but looking through the code I don't think there's actually any reason to depend on libpng at all. The package just contains png files that are used to build the cursors with xcursorgen (which hard-deps on libpng already). Unless libXcursor dlopen's libpng when it loads png-based cursors, I think the solution here is to just drop the dep?
Agreed. I've dropped the libpng dependency. commit 5c8265b84778eb77f7997f8014af652aa6005fba Author: Matt Turner <mattst88@gentoo.org> Date: Sat Oct 17 12:15:25 2015 -0700 x11-themes/xcursor-themes: Drop needless libpng dependency. Bug: https://bugs.gentoo.org/563258