media-libs/evas has no wayland useflag, and neither passes wayland related options to econf. The configure phase outputs this: --- checking whether to enable Wayland Shm rendering backend... auto checking whether Wayland Shm rendering backend will be built... yes checking whether to enable Wayland Egl rendering backend... auto checking for WAYLAND_EGL... yes checking for GL_EET... yes checking for glTexImage2D in -lGLESv2... no checking whether Wayland Egl rendering backend will be built... yes --- configure.ac:772ff show that "$(use_enable wayland wayland-shm) $(use_enable wayland wayland-egl)" would work.
Created attachment 324516 [details, diff] evas-9999.ebuild patch Attached patch fixes the issue.