D24245: Add support for passing Unix file descriptors

[Albert Astals Cid]

aacid added a reviewer: security-team.

REPOSITORY
  R283 KAuth

REVISION DETAIL
  https://phabricator.kde.org/D24245

To: volkov, fvogt, chinmoyr, cfeck, #frameworks, security-team
Cc: kde-frameworks-devel, LeGast00n, GB_2, michaelh, ngraham, bruns