Add shebang to update scripts and fix Xcode references

[tiennou]

This allows editing the scripts in Xcode and automates the building of libgit (no need to drop to the CLI anymore).

[tiennou]

I added the shebang because I'm have cmake installed through brew and Xcode wouldn't see it without it.

[jspahrsummers]

Thanks!

[tiennou]

I see you found out the weak-linking doesn't work ? Same here ;-). ld complains if it can't find the weakly-linked library. I can't see an easy workaround, short of adding libssh2 as a dependency... Your call !

[jspahrsummers]

A required dependency that big would be unfortunate. :\

Maybe we can fix up libgit2's weak linking or add our own?

[tiennou]

The problem is that we're linking libgit2 statically, which means it becomes Objective-Git responsibility to link against whatever libgit2 requires (there's already libz, libcrypto & libssl, which are "pretty big" but system-provided). So unless we switch to a "real" dynamic library (which won't fly on iOS) and make the weak-linking happen in the right place I don't think it's possible. And it still doesn't take care of the fact that libssh2 is now a required thing for linking even when weak-linked — but it shouldn't matter at runtime (a.k.a on the computer you'll install the application that uses Objective-Git).
A complete hack would be to have another target "Objective-Git-OSX + ssh". But then you have to have another one for iOS :-(.

For now, I'll keep that thing locally for working on fetching remotes (and discovering bugs ;-)).

[jspahrsummers]

HTTPS and git:// fetching should work without libssh2. In any case, I'm happy to reconsider this in the context of a PR to add fetching support.

[tiennou]

Not until libgit2/libgit2#1700 ;-)