heimdal: new package

host-heimdal is required for samba 4.1.x since it can't (yet) link
with an external heimdal implementation and can't cross-compile the
internal tools.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>