Retrieve source packages, unpack them, and build binary (.deb) packages
from them. This also installs the needed build-dependencies if needed.
$ wajig buld PKG                        (apt-get build-dep && apt-get source --build)
options:
  -n --noauth       install and build even if package(s) is untrusted
  -y --yes          install/download without yes/no prompts; use with care!
