poppler: bugfix update 0.24.4 -> .5

Also Qt4 binding bugfix.

(cherry picked from commit d37aec1ac4f855f43b9ff661a427e8555990b35f)
phonon_backend_vlc: fix build by adding pkgconfig

Commented on https://github.com/NixOS/nixpkgs/commit/86f7aec95059d8d3efba285cd51471a8aec2cb09#commitcomment-5111284

(cherry picked from commit 03c9791e0a7b65813de51c6450f126ddd62514cb)