package/libodb-boost: add host variant

Add host variant of libodb-boost required by the ODB compiler.
The libodb-boost headers are needed at compile time, and
therefore installed in $(HOST_DIR).

Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
[Arnout: add -std=c++11]
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>