For some files that had the Doom Source license attached but saw heavy external contributions over the years I added a special note to license all original ZDoom code under BSD.
To allow processing the hit through an arbitrary portal without reference to the portal group table, P_AimLineAttack and P_LineAttack need to pass some more info than just the linetarget.
We need the relative positions of shooter and target within the visual reference of the other to calculate proper angles and we need to know if such a portal was crossed at all, because a few things, e.g. seeker missiles won't work with them.
- fixed setup of target acquisition for the Mage Staff.
The pre-acquired seeker target was never passed to the spawned projectiles.
