Long story short, the insane dependencies in this ebuild can't be satisfied. Also, because they're insane repoman can't even detect how messed up they are. The package has a big || block that boils down to: gtk2-only? ( !!x11-libs/gtk+:3 x11-themes/mate-themes:0 ) ( =x11-libs/gtk+-3.16*:3 =x11-themes/mate-themes-3.16${MATE_THEMES_V}:0/3.16 ) ... which means that: a. w/ USE=-gtk2-only, it expects one of the GTK+3 versions between 3.16 and 3.22, none of which is present in Gentoo, b. w/ USE=gtk2-only, it blocks against GTK+3 which is insane. Given the package has no revdeps and is completely useless, I'd go for hastened removal.
My eyes deceived me. 3.22 is present in Gentoo, and this looks like false positive in pkgcore.
That said, please fix this mess. I told long ago how to support multiple gtk+ versions at once, BUT by now there's only 3.22 available anyways. No 3.20 is in tree, and 3.24 won't ever exist either. USE=gtk2-only doing what it does is very very very bad as well, please remove it and stop blocking a core dependency of MANY packages from a USE flag on a meta package.
Agreed: current state of gtk2 dependencies is "not good" If removing gtk2 support is all that needs done, I'm volunteering to untangle the lingering gtk2 references (meta packages or otherwise) for MATE 1.18.x branch by end of the month & move on with some minor bumps, etc. Stabilization for the MATE 1.18 branch may be needed to un-stick the legacy gtk2 support. (1.12 branch is ancient, 1.14 was buggy, and 1.16 by now is old anyway) I don't personally have time or interest in further testing & stewardship for gtk2 versions. If the plan is still to transition all of the remaining in-tree (non-overlay) MATE packages to gtk3, this should be easy enough to resolve.
looking back at keyword stablized mate-1.12-r1 ... I see the zero (0) slot is used for gtk2 mate-base/mate-1.18 (installed), depends on: x11-themes/mate-themes-meta-3-r2 (installed), depends on: x11-themes/mate-themes-3.22.7 (installed) in this case, the zero (0) slot is used as well, however: main difference seems to that without the USE=gtk2-only, x11-themes/mate-themes-3.22.7 package uses :0/3.22 slot I do not like this approach one bit.
the only ebuild in the tree looks more sane
