EGL_MESA_screen_surface version 6

[Brian Paul]

Jon Smirl wrote:
> What about opaque screen handles?
> 
>   EGLBoolean eglGetScreensMESA(EGLDisplay dpy,
>                              EGLScreen *screens, EGLint screens_size,
>                              EGLint *num_screens)
> 
> For all functions replace EGLint screen_number with EGLScreen screen
> 
> All functions that deal with these objects can return these errors:
>   EGL_LOST_SCREEN_MESA
>   EGL_LOST_MODE_MESA
>   EGL_LOST_SURFACE_MESA
> 
> And note that handle reuse should be avoided if possible to stop stale
> handles from being confused with new ones.

I've been preoccupied with other things this week.  I'll try to roll 
this into the spec by the end of tomorrow and send out version 7.

-Brian