Import libsixel-0.23.2 as graphics/libsixel.

This package provides encoder/decoder implementation for DEC SIXEL graphics, and
some converter programs.

SIXEL is one of image formats for printer and terminal imaging introduced by
Digital Equipment Corp. (DEC).
Its data scheme is represented as a terminal-friendly escape sequence.
So if you want to view a SIXEL image file, all you have to do is "cat" it to
your terminal.

(obache)