With GLX set to be deprecated in the not too distant future and EGL being in use with OpenGL ES on mobile platforms, KDE's KWin compositing window manager now has support for using desktop OpenGL over EGL instead of GLX.
For right now OpenGL over GLX is the default, but as of the latest development activity, OpenGL over EGL is also now very possible. The back-end can be controlled by the KWIN_OPENGL_WS
The deprecation of GLX in favor of EGL should happen with the new Linux OpenGL ABI
. EGL is also supported by Wayland with no support for GLX.
More information on the OpenGL EGL support in KDE's KWin can be found via Martin's blog