glxext: Send the Drawable's ID in the GLX_BufferSwapComplete event

glxext: Send the Drawable's ID in the GLX_BufferSwapComplete event

While the official INTEL_swap_event specification says that the drawable
field should contain the GLXDrawable, not the Drawable, the existing
DRI2 code in dri2.c that translates from DRI2_BufferSwapComplete sends out
GLX_BufferSwapComplete with the Drawable's ID, so existing codebases
like Clutter/Cogl rely on getting the Drawable.

Match DRI2's error here and stuff the event with the X Drawable, not
the GLX drawable.

This fixes apps seeing wrong drawables through an indirect GLX context
or with DRI3, which uses the GLX_BufferSwapComplete event directly on
the wire instead of translates Present in mesa.

At the same time, also modify the structure for the event to make sure
that clients don't make the same mistake. This is not an API or ABI
break, as GLXDrawable and Drawable are both typedefs for XID.

Signed-off-by: Jasper St. Pierre <jstpierre@mecheye.net>
Reviewed-by: Axel Davy <axel.davy@ens.fr>
Cc: "10.1 10.2" <mesa-stable@lists.freedesktop.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>