Enable pbuilder for Ubuntu/Debian to prevent build enviroment dependent issues.
Also support cross building by pbuilder.
(cross-building from Fedora 25 and Ubuntu 16.04 are tested)
Signed-off-by: Takuya ASADA <syuu@scylladb.com>
Message-Id: <20170615100230.18239-1-syuu@scylladb.com>
