Nicholas Miell authored Dec 27, 2011 and Brian Paul committed Jan 02, 2012

GLEAN::Window::~Window was calling XDestroyWindow on the currently
bound GLX drawable, which would cause the subsequent test to explode
when it called glXMakeCurrent and Mesa attempted to flush the
outstanding state to the now destroyed window.

Now the Window destructor checks if the window being destroyed is
bound to the current GLX context, and if so, releases the current GLX
context before destroying the window.

I also included the equivalent WGL change, but that is untested.
The AGL and BeOS versions are untouched, but probably needs something
similar.

With this change, the glean basic sanity test now passes on Mesa swrast.

Signed-off-by: Nicholas Miell <nmiell@gmail.com>
Signed-off-by: Brian Paul <brianp@vmware.com>