for modules, plugins and tools only (i.e. no tests nor examples)
this mimics the qmake behavior
default value is developer_build
Comes with some fixes in qmake since it seems in the qmake built it was
not having Werror, now does because we built it with add_qt_tool
Change-Id: I6f3237f25a6fedefa958644929e90f13837a12df
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>