Header not needed anymore.

We want to support Qt 5.9 for now.

This reverts commit 8837f8ca8c.

src/frontends/qt/GuiLyXFiles.cpp

@@ -613,7 +613,12 @@ void GuiLyXFiles::passParams(string const & data)
 
 void GuiLyXFiles::selectItem(QString const & item)
 {
-	QList<QTreeWidgetItem *> twi = filesLW->findItems(item, Qt::MatchExactly | Qt::MatchRecursive);
+	/* Using an intermediary variable flags is needed up to at least
+	 * Qt 5.5 because of a subtle namespace issue. See:
+	 *   https://stackoverflow.com/questions/10755058/qflags-enum-type-conversion-fails-all-of-a-sudden
+	 * for details.*/
+	Qt::MatchFlags const flags(Qt::MatchExactly|Qt::MatchRecursive);
+	QList<QTreeWidgetItem *> twi = filesLW->findItems(item, flags);
 	if (!twi.isEmpty())
 		twi.first()->setSelected(true);
 }

src/insets/InsetListingsParams.h

@@ -14,8 +14,6 @@
 
 #include "InsetCaptionable.h"
 
-#include <map>
-
 namespace lyx {
 
 class InsetListingsParams {