A buildsystem class needs to inherit or define these methods: DESCRIPTION,
check_auto_buildable, build, test, install, clean. See the comments
-inside Debian::Debhelper::Buildsystem for details.
+inside Debian::Debhelper::Buildsystem for details. Note that this interface
+is still subject to change.
Note that third-party buildsystems will not automatically be used by default,
but can be forced to be used via the --buildsystem parameter.