Merge branch 'dirfd'

* dirfd:
  slight refactoring
  remove dead comment
  refactor repo path finding
  properly close the archive
  refactor repo writing slightly
  store sigpath inside the package data
  introduce alternatives for md5/sha256sum
  simplify file_t
  port unlink to unlinkat
  fix up symlinking
  port database signing and verification to openat
  implement package signing with openat
  implement alpm_pkg_files with openat
  introduce openat for archive writing