Snippets for abootimg 0.6 from Fedora s390x

Sourced from https://kojipkgs.fedoraproject.org/packages/abootimg/0.6/37.20230721git7e127fe.fc45/data/logs/s390x/build.log.

• abootimg.c:696:3: warning: ignoring return value of ‘ftruncate’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
    696 |   ftruncate (fileno(img->stream), img->size);
        |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~