qt5: replace deprecated qStableSort with std::stable_sort
diff --git a/qt5/src/poppler-optcontent.cc b/qt5/src/poppler-optcontent.cc
index 49acd4a..56abf87 100644
--- a/qt5/src/poppler-optcontent.cc
+++ b/qt5/src/poppler-optcontent.cc
@@ -367,7 +367,7 @@
           Q_FOREACH (OptContentItem *item, changedItems) {
             indexes.append(d->indexFromItem(item, 0));
           }
-          qStableSort(indexes);
+          std::stable_sort(indexes.begin(), indexes.end());
           Q_FOREACH (const QModelIndex &changedIndex, indexes) {
             emit dataChanged(changedIndex, changedIndex);
           }
@@ -431,7 +431,7 @@
       Q_FOREACH (OptContentItem *item, changedItems) {
         indexes.append(d->indexFromItem(item, 0));
       }
-      qStableSort(indexes);
+      std::stable_sort(indexes.begin(), indexes.end());
       Q_FOREACH (const QModelIndex &changedIndex, indexes) {
         emit dataChanged(changedIndex, changedIndex);
       }