Raw.xs: Enable libgit2 threads

[jacquesg]

This PR enables the threading support in libgit2.

[jacquesg]

@ghedo I've managed to get the threading system to start up properly by putting the necessary code into a BEGIN block.

Calling the shutdown function I couldn't get to work, seems like END gets called multiple times. Do you maybe know how to solve this?

[ghedo]

The init should go into the BOOT XS section. As for the cleanup, I don't know, but AFAICT XSLoader doesn't actually "unload" an XS module, so it's probably not a big deal.

Also, I'm a bit worried about non-threaded perls (I've had troubles in the past on OpenBSD due to pthreads)., so if $Config{usethreads} is false this should probably be disable as well.

[jacquesg]

Ok, I had it in BOOT originally, but moved it to INIT as I thought there would be a symmetric way of doing it, will move it back :)

I'l also had a check for $Config{usethreads}.

[jacquesg]

Is this what you had in mind?

[ghedo]

Not quite. I meant that if $Config{usethreads} is false, GIT_THREADS shouldn't be defined at all. Without threading support in perl there's really no point in enabling threading in libgit2.

Also, why not enable this on windows too? AFAICT libgit2 supports it. We'd probably need to add -DGIT_WIN32 to MakeMaker.pm (I wonder why Makefile.embed doesn't do this though).

[jacquesg]

Haven't added the windows support yet, as it seems to be tailored towards a cygwin/mingw environment, so its quite hard to verify that it actually works.

[jacquesg]

Ok, I've enabled it for Windows, should probably be fine. Also added the GIT_WIN32 define. I don't know how well the Makefile.embed is actually maintained.

[ghedo]

Merged, thanks!