fix compiler flags for mingw64

[kkirstein]

mingw64 does not support nanosleep(), so we have to take Sleep() from the win-api (include windows.h via -DWIN32).
Currently the dependencies conf-blas & conf-lapack don't build on my cygwin/mingw64 box, but a fix should be easy...
I did not include setup.ml, configure, etc. in this PR, as on windows oasis setup introduces some backslashes in pathnames, which most probably breaks building on Linux.

[mmottl]

Thanks for the patch! Just let me know if you have suggestions on how to fix conf-blas/lapack for your platform.

[kkirstein]

Regarding conf-blas, I am still fighting with opam: I have added a shell script to determine the correct compiler (see here), like it has been done for conf-gmp, but opam does not copy files/test-win.sh to the build directory, I have put it in the same folder as opam, which seems not to be the 'idiomatic' way to to do it. So far, I could not find any hints at the opam documentation, whether files/test-win.sh needs to be registered anywhere...

[mmottl]

I'm not sure exactly either how it is supposed to work, but I have found an example in bsdowl. It contains:

remove: [
  ["sh" "%{build}%/opam/files/remove.sh" prefix]
]

Something like this might be worth trying.

[kkirstein]

Thanks for the hint, conf-blas & conf-lapack are now "building" successfully on my Windows machine. I am not sure where to send the PR: My repo is cloned from fdopen/opam-repository-mingw, but the original upstream is ocaml/opam-repository ...
BTW, I tried lacaml 8.1.0, but I still have to update setup.ml by calling oasis setup locally. Do you usually commit setup.ml after changing _oasis (if I commit my version of setup.ml the Linux build is probably broken due to Windows filepath backslashes)?

[mmottl]

@kkirstein Not sure, but it's probably easiest to just clone the ocaml/opam-repository, merge your old clone with the new clone and then submit a pull request.

Yes, I always run oasis setup, otherwise the version file would not be created correctly. I don't have problems on either Linux or Mac OS X. I wonder what exactly would make setup.ml behave incorrectly on your platform. I wouldn't want to force Oasis as a Lacaml dependency. In fact, I can't even use the "normal" Oasis output right now due to a problem with the generated myocamlbuild.ml file.

[kkirstein]

@mmottl It looks like your last commit (d2202f3) contains the correct C-compiler flags for cygwin/mingw64 in setup.ml, so it should work for 8.1.1 (no urgent to release that, as I have a working installation now).
Thanks for your support!

[mmottl]

Oh, I see, I thought you had already tried the very latest release. 8.1.1 addressed your particular problem. Glad to know it works on your platform now. It's already released.