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.
AC_USE_SYSTEM_EXTENSIONS will cause AC_PROG_CC, which is overridden by
automake-1.14, which will then init (part) of automake, in particular
am_aux_dir expansion, which in turn relies on ac_aux-dir, which is not
initialized at this point, and thus: certain doom (or fun, depending on
your POV and mood :p)
Hence call AC_USE_SYSTEM_EXTENSIONS only after AM_INIT_AUTOMAKE. This,
of course, caused a lot of related macro shuffling.
Tested against automake-1.10 (OSX Lion/XCode version) and automake-1.14
(homebrew version)
a3f86f313e