st/egl: Move module loading code to targets.
Several changes are made. libegl.a no longer defines _eglMain. It
defines functions to create and destroy a _EGLDriver instead. The
creation function is called by the targets. It takes an egl_g3d_loader
as its argument. The loader is defined by the targets and is in charge
of creating st_api and pipe_screen. This allows us to move the module
loading code to targets. Lastly, the modules are now loaded as the
respective contexts are created.
26 files changed