-t arch package target

Arch Linux provides a mixed-mode package system. While ABS/makepkg allows ports-style package building from source, the pacman installer works with binary packages.

The fpm/xpm -t arch target crafts such .pkg.txz archives, and embeds:

• .PKGINFO a meta description ini file
• .MTREE a bsdtar mode/type/gid/uid/checksum file

Generated tarballs don't carry a leading ./ for contained files. Otherwise this is a fairly standard target.

• Dependencies are listed (take note that Arch pkgnames may differ).
• License is just always listed as 'custom', no mapping yet defined.
• Build dependencies aren't mirrored (no idea what those are, and fpm doesn't have any).
• Owner/group ids are always set to root in the tarball.