This allows the WGL_SWAP_INTERVAL env var to override any application
calls to wglSwapIntervalEXT(). Useful for debugging, or to set the
interval to zero to effectively disable the swap interval.
Note: we also rename the previous instance of SVGA_SWAP_INTERVAL to
WGL_SWAP_INTERVAL since this is a WGL feature and not related to the
svga driver.
Reviewed-by: Charmaine Lee <charmainel@vmware.com>
Brian Paul
c8906b8459