EEK Cooper writes:
 > I'm glad to hear that others are facing this problem as well. Those of 
 > you who are: how are you dealing with it? Are you simply requiring your 
 > users to use a particular version of the compiler? Or switching on 
 > Sys.ocaml_version?

When we discovered the bug, we first used a test of ocaml's version at
configuration time and a  preprocessing using camlp4's pa_ifdef module
to select the  right order relation according to  ocaml's version (our
initial  order relation  or  the  inverse relation,  to  get the  same
behavior as before with the new Map.fold).

But this was not very satisfactory, and we finally rewrote our code to
be independent  of Map.fold implementation  (and we got rid  of camlp4
preprocessing, which simplified our Makefile).

-- 
Jean-Christophe Filliâtre (http://www.lri.fr/~filliatr)