aria2 is a lightweight multi-protocol & multi-source, cross platform
download utility operated in command-line.
It supports HTTP/HTTPS, FTP, SFTP, BitTorrent and Metalink.

To use OpenSSL and Expat rather than GnuTLS and libxml2 run the
script as follows:
  XML="libexpat" HTTPS="openssl" ./aria2.SlackBuild