debian/rules: add support for DEB_BUILD_OPTIONS=terse
Debian policy 4.2.0.0 adds a new "terse" option for DEB_BUILD_OPTIONS
that can be used to request a quieter build (that still shows
progress). More precisely, this allows
- showing the commands run by "make" in an abbreviated form
- suppressing irrelevant output from tests
This can be useful when building interactively since it makes it
easier to see at a glance how far the build has progressed.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>