The stw_device and its screen are set up independently. It's possible
to have a device without a screen if the DLL is loaded but never
called into, since DllMain for PROCESS_ATTACH sets up the stw_device,
but the screen is initialized later on the first call to get pixel
formats. If the DLL is loaded and then unloaded, don't crash.
Cc: mesa-stable
Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27892>
Jesse Natalie
f96d31bc8a