Major clean up of MakeContextCurrent

Rearrange most of the internals of MakeContextCurrent.	Put all of the code to
bind the new context up front.	If that is successful, unbind the old context.
This saves a lot of code and removes some locking crazyiness.

This patch has been tested for indirect rendering with glxinfo, glxgears,
manywin, and wincopy.
1 file changed