[LyX/master] Compilation fix

[Jean-Marc Lasgouttes]

commit b79a694c56bbc60d0695c8ce58d5d79e23321157
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date:   Fri Mar 22 14:39:36 2019 +0100

    Compilation fix
---
 src/frontends/qt4/GuiLyXFiles.cpp |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/src/frontends/qt4/GuiLyXFiles.cpp 
b/src/frontends/qt4/GuiLyXFiles.cpp
index bcb2dcd..89623b7 100644
--- a/src/frontends/qt4/GuiLyXFiles.cpp
+++ b/src/frontends/qt4/GuiLyXFiles.cpp
@@ -550,7 +550,12 @@ 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);
 }