Snippets for a2jmidid 9 from Fedora s390x

Sourced from https://kojipkgs.fedoraproject.org/packages/a2jmidid/9/21.fc45/data/logs/s390x/build.log.

• ../jack.c:64:18: warning: variable ‘now’ set but not used [-Wunused-but-set-variable=]
     64 |   jack_nframes_t now;
        |                  ^~~
  

• ../jack.c:326:7: warning: variable ‘err’ set but not used [-Wunused-but-set-variable=]
    326 |   int err;
        |       ^~~