Prefer rvalue version of toLocal8Bit()

... to re-use existing buffers.

Change-Id: I5907a2e29d7f7dac04df5bf50769b47131e175d8
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/plugins/platforms/xcb/qxcbintegration.cpp

@@ -466,7 +466,7 @@ QByteArray QXcbIntegration::wmClass() const
         }
 
         if (!name.isEmpty() && !className.isEmpty())
-            m_wmClass = name.toLocal8Bit() + '\0' + className.toLocal8Bit() + '\0';
+            m_wmClass = std::move(name).toLocal8Bit() + '\0' + std::move(className).toLocal8Bit() + '\0';
     }
     return m_wmClass;
 }

src/plugins/sqldrivers/psql/qsql_psql.cpp

@@ -911,7 +911,7 @@ bool QPSQLDriver::open(const QString & db,
         connectString.append(QLatin1Char(' ')).append(opt);
     }
 
-    d->connection = PQconnectdb(connectString.toLocal8Bit().constData());
+    d->connection = PQconnectdb(std::move(connectString).toLocal8Bit().constData());
     if (PQstatus(d->connection) == CONNECTION_BAD) {
         setLastError(qMakeError(tr("Unable to connect"), QSqlError::ConnectionError, d));
         setOpenError(true);

src/printsupport/kernel/qprintengine_win.cpp

@@ -106,7 +106,7 @@ static QByteArray msgBeginFailed(const char *function, const DOCINFO &d)
        str << ", document \"" << QString::fromWCharArray(d.lpszDocName) << '"';
     if (d.lpszOutput && d.lpszOutput[0])
         str << ", file \"" << QString::fromWCharArray(d.lpszOutput) << '"';
-    return result.toLocal8Bit();
+    return std::move(result).toLocal8Bit();
 }
 
 bool QWin32PrintEngine::begin(QPaintDevice *pdev)

src/tools/qdbuscpp2xml/qdbuscpp2xml.cpp

@@ -447,7 +447,7 @@ int main(int argc, char **argv)
     output.write("<node>\n");
     for (const ClassDef &cdef : qAsConst(classes)) {
         QString xml = qDBusGenerateClassDefXml(&cdef);
-        output.write(xml.toLocal8Bit());
+        output.write(std::move(xml).toLocal8Bit());
     }
     output.write("</node>\n");