Merge remote-tracking branch 'origin/2.8' into HEAD

Conflicts:
	qtcreator.pri
	qtcreator.qbs

Change-Id: I5d2018d3437b99bcdffa92bf1a212f42923c4fad

src/plugins/cpptools/cpppreprocessor.cpp

@@ -233,7 +233,7 @@ QString CppPreprocessor::resolveFile_helper(const QString &fileName, IncludeType
 
     foreach (const QString &includePath, m_includePaths) {
         QString path = includePath + fileName;
-        if (checkFile(path))
+        if (m_workingCopy.contains(path) || checkFile(path))
             return path;
     }