Makefile calls an illegal option of 'date' in OSX

[beurdouche]

Another dumb OSX bug when $ make -C src/ocaml_output...

date: illegal option -- I
usage: date [-jnu] [-d dst] [-r seconds] [-t west] [-v[+|-]val[ymwdHMS]] ... 
            [-f fmt date | [[[mm]dd]HH]MM[[cc]yy][.ss]] [+format]
echo 'let version = "0.9.2.0"' > FStar_Version.ml
echo 'let platform = "Darwin_x86_64"' >> FStar_Version.ml
echo 'let compiler = "OCaml 4.02.3"' >> FStar_Version.ml
echo 'let date = ""' >> FStar_Version.ml
echo 'let commit= "af92eed"' >> FStar_Version.ml

[beurdouche]

Fixed by 85f3ba4