As a result, EGL_NONE is no longer a valid client API. And it is
possible that no config supports the current bound API.
Signed-off-by: Chia-I Wu <olvaffe@gmail.com>
Current thread management was initialized in _eglInitGlobals, which is
called only in eglGetDisplay. Since EGL does not require eglGetDisplay
to be called first, the initialization is better to be done on demand.
_eglFiniCurrent is removed, as it is not called at all.
Signed-off-by: Chia-I Wu <olvaffe@gmail.com>