Modify amide port to use ffmpeg 3.x

Actual patch is a mix of work from subitter and my modifications
based on debian patch from [1]

While here, fix the DCMTK option.

PR: 215240
Submitted by: jbeich
Obtained From: https://anonscm.debian.org/viewvc/debian-med/trunk/packages/amide/trunk/debian/patches/libav10.patch?view=markup&pathrev=16327 [1]