fix some compiler warnings

fix some compiler warnings

upstream commits that make questionable changes and need further investigation:
https://github.com/qtproject/qtxmlpatterns/commit/4bd45d7d2a32a170b4ed11b03752726b446fbb79
https://github.com/qtproject/qtbase/commit/336eac089623be3c824b19a1161d19906ae6125f

upstream commits:
https://github.com/qtproject/qtbase/commit/6a11dd166985d7804b6861662193093aa84cdd0c
https://github.com/qtproject/qtxmlpatterns/commit/8a95cb56f5ecadb450de545061e8444e9698d21f
https://github.com/qtproject/qtbase/commit/c550a5d42c1188c0ccd11c205665e2608dbec61f

Signed-off-by: Ivailo Monev <xakepa10@gmail.com>