This commit makes Looking Glass always use the OpenGL renderer when
running on Wayland. The EGL renderer is broken on Wayland and can't
reasonably be fixed until SDL is dropped entirely (as per
https://github.com/gnif/LookingGlass/issues/306).
Until that time, the OpenGL renderer provides a much better
Wayland-native experience.
This change allows us to look for and filter out the warp completion
event as we can obtain and use the serial number of the warp request to
do so. This is far more elegant then the x/y match that we were doing
prior.
eglSwapBuffers is allowed to block when called with a nonzero interval
parameter. On Wayland, Mesa will block until a frame callback arrives.
If an application is not visible, a compositor is free to not schedule
frame callbacks (in order to save CPU time rendering something that is
entirely invisible).
Currently, starting Looking Glass from a terminal, hiding it
entirely, and sending ^C will cause Looking Glass to hang joining the
render thread until the window is made visible again.
Calling eglDestroySurface is insufficient to unblock eglSwapBuffers, as
it attempts to grab the same underlying mutex.
Instead, this commit makes it so that we pass a 0 interval to
eglSwapBuffers when running on Wayland, such that we don't block waiting
for a frame callback. This is not entirely ideal as it *does* mean
Looking Glass submits buffers while hidden, but it seems better than
hanging on exit.
It also forces opengl:vsync and egl:vsync flags to off when running on
Wayland, as they are meaningless there.
This means if someone checks out a tagged revision, the extra commit N
and commit hash are removed from the VERSION, leaving just the tag name
Adding any commits will cause -<commitssince>-g<commithash> to return.
The dirty worktree '+' still functions as normal, simply appended to
the end of the tag name, like 'v1.0.3+'. With both extra commits and a
dirty worktree, it will look like 'v1.0.3-2-gd6e00e4f34a+', as usual.
The --dirty argument of git describe performs the same function as the
now-removed git diff logic.
It will add its argument (default '-dirty') to the end of the revision.
Providing '+' as the argument replicates old behavior.
