Lower half is getting eaten by something, presumably underflow as it's black.
Make EGL and DRM coexist; make ensure_win_resources safe to call regardless
of what resources we want, so outer code doesn't have to care.
Get steamcompmgr's GL context from EGL and rip out GLX, as we need EGL to
import dma-bufs.
When new buffers are committed to surfaces, push their information to
steamcompmgr (without any feedback for now, fire-and-forget).
Can render games now.
Enable C++ for bits of the code, but nothing that includes wlroots as that
doesn't want to build as C++.
Enable SubstructureRedirectMask mode and handle MapRequest for now; this lets
us get the WL_SURFACE_ID ClientMessages.
This uses a build of wlroots that has its internal XWM ripped out.
