* comments: mark "emulated" (windows) functions

[SLG]

* INRIA request for extended UNIX:
  http://caml.inria.fr/mantis/view.php?id=5063
  http://caml.inria.fr/mantis/view.php?id=2533 (<- very interesting)
  http://caml.inria.fr/mantis/view.php?id=3851
  http://caml.inria.fr/mantis/view.php?id=480

Wanted functions:
* sysconf: get system configuration constants. In particular, PAGESIZE,
  _SC_PHYS_PAGES, _SC_AVPHYS_PAGES, _SC_NPROCESSORS_CONF, _SC_NPROCESSORS_ONLN 
  (see Jane Street Core)
* sysinfo (see Jane Street Core)
* mkdtemp (see Jane Street Core)
