Fix build on macOS

If you use ostream you should include ostream

Change-Id: I50701eacd6f2a526d76283ba24303d3fb7a783bf
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

src/tools/clangbackend/ipcsource/clangjobrequest.cpp

@@ -27,6 +27,8 @@
 
 #include <QFileInfo>
 
+#include <ostream>
+
 namespace ClangBackEnd {
 
 #define RETURN_TEXT_FOR_CASE(enumValue) case JobRequest::Type::enumValue: return #enumValue