LAME has just been added to Fedora 25 and newer (still in updates-testing with buildroot override in place). Audacious' filewriter plugin should now be able to add MP3 output support by adding BuildRequires: lame-devel to audacious-plugins.spec.
audacious-plugins-3.8.2-3.fc25 has been submitted as an update to Fedora 25. https://bodhi.fedoraproject.org/updates/FEDORA-2017-7725b051a5
audacious-plugins-3.8.2-3.fc26 has been submitted as an update to Fedora 26. https://bodhi.fedoraproject.org/updates/FEDORA-2017-4d4e8fca17
audacious-plugins-3.8.2-3.fc25 has been pushed to the Fedora 25 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2017-7725b051a5
audacious-plugins-3.8.2-3.fc26 has been pushed to the Fedora 26 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2017-4d4e8fca17
audacious-plugins-3.8.2-3.fc26 has been pushed to the Fedora 26 stable repository. If problems still persist, please make note of it in this bug report.
audacious-plugins-3.8.2-3.fc25 has been pushed to the Fedora 25 stable repository. If problems still persist, please make note of it in this bug report.