glxCopyContext() may throw X errors and cause the current process to exit. For example, Mesa doesn't
support glxCopyContext() for direct rendering contexts and ends up using the code path for indirect
rendering contexts. When Xorg receives such requests, it rejects them because they're for direct
rendering contexts and reports an X error. We also can't use indirect rendering context because
it needs to be explicitly enabled in xorg.conf and has poor performance. So handle this error before
graphics drivers implement the support.

Fix Cladun X2 crash at start.
Signed-off-by: Zhiyi Zhang <zzhang@codeweavers.com>