Fix misnamed variable causing build failure with USE=-mp3
https://bugs.gentoo.org/767760
Signed-off-by: Ionen Wolkens <sudinave@gmail.com>
--- a/mscore/exportdialog.cpp
+++ b/mscore/exportdialog.cpp
@@ -77,5 +77,5 @@
       // Disable .mp3 option if unavailable
       QStandardItem* mp3Item = fileTypeComboBoxModel->item(3);
-      mp3Item->setFlags(audioItem->flags() & ~Qt::ItemIsEnabled);
+      mp3Item->setFlags(mp3Item->flags() & ~Qt::ItemIsEnabled);
 # endif
 # ifndef HAS_AUDIOFILE