Workaround for NVIDIA bug in glXSwapIntervalEXT.

       This works around a bug in NVIDIA's implementation of
       glXSwapIntervalEXT, where it ignores updates to what it *thinks* is the
       current value, even though glXQueryDrawable returns a different value.

       Bug reported to NVIDIA and will hopefully be a part of 319.xx.

       Also a fix for invalidly treating glXSwapIntervalEXT as having an int
       return value (it's void).
Fixed compiler warning (and undefined behavior) in game controller event filter.
Backed out use of @autorelease keyword for now, since it's not supported by older Xcode versions.
Backed out use of @autorelease keyword for now, since it's not supported by older Xcode versions.