structs: Adjust %remote-callbacks for libgit2 v1.2.0.
Fixes #23 (closed).
- configure.ac (AC_CHECK_MEMBER) <git_remote_callbacks.remote_ready>: New member check. <git_remote_callbacks.resolve_url>: Streamline.
- git/config.scm.in (%have-remote-callbacks-remote-ready?): New variable.
- git/structs.scm (%remote-callbacks): Conditionally add the new callback 'remote_ready' callback field.