QT_USE_QSTRINGBUILDER to fix source compatibility

In 4.8 we added support for using StringBuilder with QByteArray.
But this is breaking source compatibility for people that used
QT_USE_FAST_OPERATOR_PLUS in Qt 4.7. So we introduce a new macro

Notice that QT_USE_FAST_CONCATENATION was not working without
QT_USE_FAST_OPERATOR_PLUS, so we remove the checking of that macro.

Reviewed-by: joao

1 files changed, 3 insertions, 7 deletions

diff --git a/src/corelib/tools/qstring.cpp b/src/corelib/tools/qstring.cpp
index 5493ba9..3b3f715 100644
--- a/src/corelib/tools/qstring.cpp
+++ b/src/corelib/tools/qstring.cpp
@@ -777,16 +777,12 @@ const QString::Null QString::null = { };
 
     \snippet doc/src/snippets/qstring/stringbuilder.cpp 5
 
-    A more global approach is to include this define:
+    A more global approach which is the most convenient but
+    not entirely source compatible, is to this define in your
+    .pro file:
 
     \snippet doc/src/snippets/qstring/stringbuilder.cpp 3
 
-    and use \c{'%'} instead of \c{'+'} for string concatenation
-    everywhere. The third approach, which is the most convenient but
-    not entirely source compatible, is to include two defines:
-
-    \snippet doc/src/snippets/qstring/stringbuilder.cpp 4
-
     and the \c{'+'} will automatically be performed as the
     \c{QStringBuilder} \c{'%'} everywhere.