D11434: Fix build with Qt 5.11 (missing headers)

[Albert Astals Cid]

aacid accepted this revision.
This revision is now accepted and ready to land.

REPOSITORY
  R34 Marble

BRANCH
  master

REVISION DETAIL
  https://phabricator.kde.org/D11434

To: asturmlechner, #marble, aacid
Cc: #kde_edu, narvaez, apol, marble-devel