Re: Segmentation violation

from the libxcb patch notes

   This is a workaround for X11 applications which have locking bugs
  that will trigger assertions when libxcb is used. An environment variable,
  LIBXCB_ALLOW_SLOPPY_LOCK, can be set to skip the check that the display lock
  has been set correctly. This will not be merged upstream as the XCB
  developers have decided to be strict in exposing the bugs so they are fixed
  in the appropriate location.

could they be any more vague?  is there a sensible note somewhere that
defines "locking bugs" "set correctly" "appropriate location"?
i couldn't find it on a quick google.
i did find that quite a few applications seem to need it.
i suppose i am happy if Inferno is not one of them, so it would
be useful to know what the problem actually is.