Snippets for libebml 1.4.7 from Fedora s390x

Sourced from https://kojipkgs.fedoraproject.org/packages/libebml/1.4.7/1.fc46/data/logs/s390x/build.log.

• /builddir/build/BUILD/libebml-1.4.7-build/libebml-1.4.7/src/EbmlElement.cpp:248:12: warning: variable ‘ReadSize’ set but not used [-Wunused-but-set-variable=]
    248 |     uint32 ReadSize = 0;
        |            ^~~~~~~~