glx: add fail check for current context in another thread
The GLX spec for glXMakeCurrent (3.3): "If ctx is current to some other thread, then glXMakeCurrent will generate a BadAccess error"
The GLX spec for glXCopyContext (3.3): "If the destination context is current for some thread then a BadAccess error is generated"
Closes: #7961 (closed) Signed-off-by: Illia Polishchuk illia.a.polishchuk@globallogic.com
Edited by Illia Polishchuk