glx: proposed fix for setSwapInterval
When mesa gets a DRI2 1.1 connection (as experienced with vmwware DDX) we don't get a pointer for this.
Don't explode just keep going.
Fixes: 60ebeb46 ("glx: Implement GLX_EXT_swap_control for DRI2 and DRI3")
When mesa gets a DRI2 1.1 connection (as experienced with vmwware DDX) we don't get a pointer for this.
Don't explode just keep going.
Fixes: 60ebeb46 ("glx: Implement GLX_EXT_swap_control for DRI2 and DRI3")