Currently, qtwayland requires all of qt being compiled from git. However, it compiles fine against 5.3.0_rc. Lowering the dependency (and possibly adding a warning that Qt from git may be required in the future) would allow people to test qtwayland without having to compile all of Qt from git. Reproducible: Always
Sorry, won't happen. It usually compiles around this time, when 5.x.0 is about to be released or has just been released, and the stable branch is still 5.x.9999, thus no big changes are committed. But it'll most likely break as soon as dev in merged into stable and becomes 5.(x+1).9999. Since you're using a live ebuild from an overlay, I assume you know how to tell emerge to ignore a dependency, or to modify the ebuild yourself.