autoconf-archive: 2017.09.28 -> 2018.03.13

Semi-automatic update generated by https://github.com/ryantm/nix-update tools. These checks were done:

- built on NixOS
- Warning: no binary found that responded to help or version flags. (This warning appears even if the package isn't expected to have binaries.)
- found 2018.03.13 with grep in /nix/store/gpwn8923mppc2h6vx2rgg8q52ss2mg2l-autoconf-archive-2018.03.13
- directory tree listing: https://gist.github.com/eaaa4f78b6bd461710c33aea9e21fdea