The ebuild should not allow attempting to build when USE="scrobbler" is set but USE="gtk" is not, since ./configure will fail with `configure: error: --enable-scrobbler2 cannot be used without --enable-gtk`.
One more error: configure: error: --enable-notify cannot be used without --enable-gtk
if you do a normal ./configure --enable-qt, it disables scrobbler by default, as well as a bunch of other things. Building with --enable-qt --enable-gtk pretty much enables everything in the configure script (provided you have all other deps installed already), so perhaps the ebuild needs to be adjusted a little to reflect this; USE flags such as -scrobbler would assume ./configure --disable-scrobbler, otherwise enable by default.
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=beae50663486be82a96836334c9e45d1b4416d40 commit beae50663486be82a96836334c9e45d1b4416d40 Author: David Seifert <soap@gentoo.org> AuthorDate: 2017-11-05 11:49:02 +0000 Commit: David Seifert <soap@gentoo.org> CommitDate: 2017-11-05 11:49:02 +0000 media-plugins/audacious-plugins: Version bump to 3.9 Closes: https://bugs.gentoo.org/564466 Closes: https://bugs.gentoo.org/572334 Closes: https://bugs.gentoo.org/572796 Closes: https://bugs.gentoo.org/573886 Closes: https://bugs.gentoo.org/573888 Closes: https://bugs.gentoo.org/590008 Closes: https://bugs.gentoo.org/611106 Closes: https://bugs.gentoo.org/636318 Closes: https://bugs.gentoo.org/636320 Package-Manager: Portage-2.3.13, Repoman-2.3.4 media-plugins/audacious-plugins/Manifest | 1 + .../audacious-plugins/audacious-plugins-3.9.ebuild | 164 +++++++++++++++++++++ .../audacious-plugins-9999.ebuild | 164 +++++++++++++++++++++ media-plugins/audacious-plugins/metadata.xml | 46 +++--- 4 files changed, 353 insertions(+), 22 deletions(-)