diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6465564a4..16d2ba919 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -11,6 +11,7 @@ macro_optional_find_package(QImageBlitz)
 macro_log_feature(QIMAGEBLITZ_FOUND "QImageBlitz" "An image effects library" "http://sourceforge.net/projects/qimageblitz" TRUE "kdesupport" "Required to build Okular.")
 
 add_definitions(${QT_DEFINITIONS} ${KDE4_DEFINITIONS})
+add_definitions(-DQT_USE_FAST_CONCATENATION -DQT_USE_FAST_OPERATOR_PLUS)
 include_directories(
    ${CMAKE_CURRENT_SOURCE_DIR}
    ${KDE4_INCLUDES}
diff --git a/generators/chm/generator_chm.cpp b/generators/chm/generator_chm.cpp
index f48ec02a8..2619ade0e 100644
--- a/generators/chm/generator_chm.cpp
+++ b/generators/chm/generator_chm.cpp
@@ -181,7 +181,7 @@ bool CHMGenerator::doCloseDocument()
 
 void CHMGenerator::preparePageForSyncOperation( int zoom , const QString & url)
 {
-    KUrl pAddress= "ms-its:" + m_fileName + "::" + url;
+    KUrl pAddress= QString("ms-its:" + m_fileName + "::" + url);
     m_chmUrl = url;
     m_syncGen->setZoomFactor(zoom);
     m_syncGen->openUrl(pAddress);
@@ -278,7 +278,7 @@ void CHMGenerator::generatePixmap( Okular::PixmapRequest * request )
         , static_cast<double>(requestHeight)/static_cast<double>(request->page()->height())
         ) ) * 100;
 
-    KUrl pAddress= "ms-its:" + m_fileName + "::" + url;
+    KUrl pAddress= QString("ms-its:" + m_fileName + "::" + url);
     m_chmUrl = url;
     m_syncGen->setZoomFactor(zoom);
     m_syncGen->view()->resize(requestWidth,requestHeight);
diff --git a/generators/dvi/dviexport.cpp b/generators/dvi/dviexport.cpp
index 4aa4ce588..f866559d7 100644
--- a/generators/dvi/dviexport.cpp
+++ b/generators/dvi/dviexport.cpp
@@ -205,7 +205,7 @@ bool find_exe(const QString& exe_)
   const iterator end = path.end();
   for (iterator it = path.begin(); it != end; ++it) {
     const QString dir = it->endsWith("/") ? *it : *it + '/';
-    const QFileInfo abs_exe = dir + exe.filePath();
+    const QFileInfo abs_exe = QString(dir + exe.filePath());
 
     if (abs_exe.exists())
       return abs_exe.isReadable() && abs_exe.isExecutable();