sync up with qt creator - for qmake itself, this is just a minor
refactoring.
Change-Id: I833253f81c3159056fab2ff888f293b36cc2ef56
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
(cherry picked from qtcreator/66802ef8bf7989dc025e34bf91d93576189c483c)
(cherry picked from qtcreator/69542826fa643a0fed2fc9e717f072c2852dc017)
(cherry picked from qtcreator/196424115338fb9a535810704b7d814d318b0462)
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
