media-sound/flacon: Add media-libs/taglib:= slot op, ABI break imminent

Ninja-edit after 2d5ea29c69

Bug: https://bugs.gentoo.org/943160
Signed-off-by: Andreas Sturmlechner <asturm@gentoo.org>

media-sound/flacon/flacon-11.4.0.ebuild

@@ -23,7 +23,7 @@ BDEPEND="
 RDEPEND="
 	app-i18n/uchardet
 	dev-qt/qtbase:6[gui,network,widgets,concurrent]
-	media-libs/taglib
+	media-libs/taglib:=
 	media-sound/sox[flac,wavpack]
 	media-video/mediainfo
 "