tzdump: new host package

tzdump takes timezone info in the installed tzdata format, and
outputs timezone info parseable by uClibc.

[Peter: adjust host-zip dep, simplify build/install, use INSTALL variable]
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
[yann.morin.1998@free.fr: split zic header-install to its own cset]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>