diff --git a/graphics/dspdfviewer/files/patch-dspdfviewer.cpp b/graphics/dspdfviewer/files/patch-dspdfviewer.cpp
index c402cef12a87..d9e8b04e8a54 100644
--- a/graphics/dspdfviewer/files/patch-dspdfviewer.cpp
+++ b/graphics/dspdfviewer/files/patch-dspdfviewer.cpp
@@ -6,6 +6,19 @@ Fix build with Clang 8:
 
 --- dspdfviewer.cpp.orig	2016-09-13 13:18:47 UTC
 +++ dspdfviewer.cpp
+@@ -292,10 +292,10 @@ void DSPDFViewer::sendAllClockSignals() const
+   emit presentationClockUpdate(presentationClock());
+ }
+ 
+-QTime DSPDFViewer::timeSince(const QTime& startPoint) const
++QTime DSPDFViewer::timeSince(const QElapsedTimer& startPoint) const
+ {
+   QTime result(0,0);
+-  result = result.addMSecs(startPoint.elapsed());
++  result = result.addMSecs(static_cast<int>(startPoint.elapsed()));
+   return result;
+ }
+ 
 @@ -308,7 +308,7 @@ RenderingIdentifier DSPDFViewer::toRenderIdent(unsigne
  
  RenderingIdentifier DSPDFViewer::toThumbnailRenderIdent(unsigned int pageNumber, PDFViewerWindow& window)
diff --git a/graphics/dspdfviewer/files/patch-dspdfviewer.h b/graphics/dspdfviewer/files/patch-dspdfviewer.h
new file mode 100644
index 000000000000..f673089ad69b
--- /dev/null
+++ b/graphics/dspdfviewer/files/patch-dspdfviewer.h
@@ -0,0 +1,30 @@
+--- dspdfviewer.h.orig	2016-09-13 13:18:47 UTC
++++ dspdfviewer.h
+@@ -22,6 +22,7 @@
+ #define dspdfviewer_H
+ 
+ #include <QObject>
++#include <QElapsedTimer>
+ #include <QTimer>
+ #include <QFileSystemWatcher>
+ #include "poppler-qt.h"
+@@ -42,8 +43,8 @@ class DSPDFViewer: public QObject (private)
+ 
+ private:
+   QTimer	clockDisplayTimer;
+-  QTime 	slideStart;
+-  QTime		presentationStart;
++  QElapsedTimer 	slideStart;
++  QElapsedTimer		presentationStart;
+   bool		presentationClockRunning;
+ 
+ private:
+@@ -89,7 +90,7 @@ private slots: (public)
+     QTime slideClock() const;
+     QTime presentationClock() const;
+ 
+-    QTime timeSince( const QTime& startPoint) const;
++    QTime timeSince( const QElapsedTimer& startPoint) const;
+ 
+     bool isAudienceScreenBlank() const;
+