Revert "compile everything with QT_USE_FAST_CONCATENATION"

This reverts commit e70530c5ad85c1c44fca99be04d5e37043d3baca. It
did break builds on older gcc versions (gcc 4.1.2 64 bit Linux,
gcc 4.0.1 on Mac OS X):

parser/qmljsgrammar_p.h: In static member function ???static int
QmlJSGrammar::nt_action(int, int)???:
parser/qmljsgrammar_p.h:188: error: ???QmlJSGrammar::<anonymous enum>???
is/uses anonymous type
parser/qmljsgrammar_p.h:188: error:   trying to instantiate
???template<class T> struct QConcatenable???
...

5 files changed, 9 insertions, 10 deletions

diff --git a/src/plugins/debugger/registerhandler.cpp b/src/plugins/debugger/registerhandler.cpp
index b74af0fc265..9b6cb4e015b 100644
--- a/src/plugins/debugger/registerhandler.cpp
+++ b/src/plugins/debugger/registerhandler.cpp
@@ -79,18 +79,18 @@ QVariant RegisterHandler::data(const QModelIndex &index, int role) const
         // Return some address associated with the register.
         bool ok = true;
         qulonglong value = reg.value.toULongLong(&ok, 0);
-        return ok ? QVariant(QString::fromLatin1("0x") + QString::number(value, 16)) : QVariant();
+        return ok ? QString::fromLatin1("0x") + QString::number(value, 16) : QVariant();
     }
 
     const QString padding = "  ";
     if (role == Qt::DisplayRole) {
         switch (index.column()) {
-            case 0: return QVariant(padding + reg.name + padding);
+            case 0: return padding + reg.name + padding;
             case 1: {
                 bool ok = true;
                 qulonglong value = reg.value.toULongLong(&ok, 0);
                 QString res = ok ? QString::number(value, m_base) : reg.value;
-                return QVariant(QString(m_strlen - res.size(), QLatin1Char(' ')) + res);
+                return QString(m_strlen - res.size(), QLatin1Char(' ')) + res;
             }
         }
     }
diff --git a/src/plugins/debugger/watchhandler.cpp b/src/plugins/debugger/watchhandler.cpp
index 35a9545c7b8..83d4fd48137 100644
--- a/src/plugins/debugger/watchhandler.cpp
+++ b/src/plugins/debugger/watchhandler.cpp
@@ -804,7 +804,7 @@ QVariant WatchModel::data(const QModelIndex &idx, int role) const
             switch (idx.column()) {
                 case 0:
                     if (data.name == QLatin1String("*") && item->parent)
-                        return QVariant(QLatin1Char('*') + item->parent->name);
+                        return QLatin1Char('*') + item->parent->name;
                     return data.name;
                 case 1: {
                     int format = m_handler->m_individualFormats.value(data.iname, -1);
diff --git a/src/plugins/help/helpplugin.cpp b/src/plugins/help/helpplugin.cpp
index f7bbfbeb704..bba6b55ffd0 100644
--- a/src/plugins/help/helpplugin.cpp
+++ b/src/plugins/help/helpplugin.cpp
@@ -139,7 +139,7 @@ bool HelpPlugin::initialize(const QStringList &arguments, QString *error)
 
     // FIXME shouldn't the help engine create the directory if it doesn't exist?
     const QFileInfo &fi(m_core->settings()->fileName());
-    const QDir directory(fi.absolutePath() + QLatin1Literal("/qtcreator"));
+    const QDir &directory(fi.absolutePath()+"/qtcreator");
     if (!directory.exists())
         directory.mkpath(directory.absolutePath());
     m_helpEngine = new QHelpEngine(directory.absolutePath() +
@@ -976,8 +976,8 @@ void HelpPlugin::openHelpPage(const QString& url)
         } else {
             urlPrefix = QLatin1String("http://doc.trolltech.com/latest/");
         }
-        QDesktopServices::openUrl(QUrl(urlPrefix + url.mid(url
-            .lastIndexOf(QLatin1Char('/')) + 1)));
+        QDesktopServices::openUrl(urlPrefix + url.mid(url
+            .lastIndexOf(QLatin1Char('/')) + 1));
     }
 }
 
diff --git a/src/plugins/projectexplorer/toolchain.cpp b/src/plugins/projectexplorer/toolchain.cpp
index d6966754fbd..4f964e64656 100644
--- a/src/plugins/projectexplorer/toolchain.cpp
+++ b/src/plugins/projectexplorer/toolchain.cpp
@@ -438,8 +438,7 @@ void MSVCToolChain::addToEnvironment(ProjectExplorer::Environment &env)
                 return;
             QString filename = tf.fileName();
             tf.write("call \"" + varsbat.toLocal8Bit()+"\"\r\n");
-            QString redirect = "set > \"" + QDir::tempPath() + "\\qtcreator-msvc-environment.txt\"\r\n";
-            tf.write(redirect.toLocal8Bit());
+            tf.write(("set > \"" + QDir::tempPath() + "\\qtcreator-msvc-environment.txt\"\r\n").toLocal8Bit());
             tf.flush();
             tf.waitForBytesWritten(30000);
 
diff --git a/src/plugins/qt4projectmanager/customwidgetwizard/plugingenerator.cpp b/src/plugins/qt4projectmanager/customwidgetwizard/plugingenerator.cpp
index 5c6abb3ccdf..5e22af5ae51 100644
--- a/src/plugins/qt4projectmanager/customwidgetwizard/plugingenerator.cpp
+++ b/src/plugins/qt4projectmanager/customwidgetwizard/plugingenerator.cpp
@@ -127,7 +127,7 @@ QList<Core::GeneratedFile>  PluginGenerator::generatePlugin(const GenerationPara
                     QLatin1String(", ") +
                     wo.pluginClassName +
                     QLatin1Char(')') :
-                QString());
+                QLatin1String(""));
         const QString pluginSourceContents = processTemplate(p.templatePath + QLatin1String("/tpl_single.cpp"), sm, errorMessage);
         if (pluginSourceContents.isEmpty())
             return QList<Core::GeneratedFile>();