That should help setting it up on a machine that might want to use normal
wlroots for other things. Resolve a GL symbol conflict now that we're
colocated with wlroots' dynamic loading code.
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.
