diff --git a/src/plugins/texteditor/basetextdocument.cpp b/src/plugins/texteditor/basetextdocument.cpp
index f22bc2a8385..665dd5617aa 100755
--- a/src/plugins/texteditor/basetextdocument.cpp
+++ b/src/plugins/texteditor/basetextdocument.cpp
@@ -47,7 +47,11 @@
 
 using namespace TextEditor;
 
+#if defined (Q_OS_WIN)
+QT_BEGIN_NAMESPACE
 extern Q_CORE_EXPORT int qt_ntfs_permission_lookup;
+QT_END_NAMESPACE
+#endif
 
 #if defined (Q_OS_WIN)
 # define NATIVE_LINE_TERMINATOR CRLFLineTerminator
@@ -145,14 +149,14 @@ bool BaseTextDocument::isReadOnly() const
 
     const QFileInfo fi(m_fileName);
 
-#ifdef Q_OS_WIN32
+#ifdef Q_OS_WIN
     // Check for permissions on NTFS file systems
     qt_ntfs_permission_lookup++;
 #endif
 
     const bool ro = !fi.isWritable();
 
-#ifdef Q_OS_WIN32
+#ifdef Q_OS_WIN
     qt_ntfs_permission_lookup--;
 #endif
     return ro;