Function libgit2_sys::git_diff_index_to_index

pub unsafe extern "C" fn git_diff_index_to_index(
    diff: *mut *mut git_diff, 
    repo: *mut git_repository, 
    old_index: *mut git_index, 
    new_index: *mut git_index, 
    opts: *const git_diff_options
) -> c_int