If we're building a package for more than one architecture and
the source package provides architecture 'any' *and* 'all' binary
packages at the same time we've to build on all but one
architecture using the -B build option (see dpkg-buildpackage(1)
Setting MAIN_ARCHITECTURE allows choosing the main architecture,
which is the one providing the "Architecture: all" binary
packages. If unset it defaults to the architecture of the host
Restructure the code to make it less ugly...
Setting TRUNK_RELEASE allows copying each package to
a specific repository so you get a "release-trunk"
feature to point sources.list to a repository featuring
always the latest package versions.