moc warnings output on stderr

When moc uses a warning like "No relevant classes found", it output the message on stderr (cf. qtbase\src\tools\moc\parser.cpp, Parser::warning / Parser::note)

Unfortunately, when invoking a bash script to moc from XCode, the warning is transformed as an error. Massage is:

Command /bin/sh emitted errors but did not return a nonzero exit code to indicate failure

It would be more coherent to use stdout and not stderr for warnings.