Debian Packaging work for WireGuard:

 * consider make check for wg during build: this depends on
   scan-build, which is part of clang, but also wants to clean the
   build tree first.  Currently, we don't do any build-time tests.

 * autopkgtest:

  - from src/, run "make check" (depending on clang-tools and sparse)
    and make sure it looks plausible.

  - Run the kvm-based test suite on infrastructure that can support it
    (using appropriate autopkgtest Restrictions)

  - Think about flakiness markers for network-based tests if the
    network is bad or the test server is offline (see also
    https://salsa.debian.org/ci-team/autopkgtest/merge_requests/61)

  - Can we add other tests?
