buildroot

libarchive: add selection of bsdcat

libarchive builds three commandline utilities: bsdtar, bsdcpio, and
bsdcat. This change adds control over the third utility to the list of
configuration options.

Signed-off-by: Frank Hunleth <fhunleth@troodon-software.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>