Merge remote-tracking branch 'qatar/master'

* qatar/master:
  configure: Use linker hardening flags on mingw
  vc1: Make INIT_LUT() self contained
  vc1: Simplify code by using INIT_LUT()
  vc1: Move INIT_LUT() further up to allow using it in more places
  vc1dec: Remove some now unused variables
  vc1dec: Do not allow field_mode to change after the first header
  vc1, mss2: Check for any negative return value from ff_vc1_parse_frame_header
  vc1dec: Fix current ptr selection in vc1_mc_4mv_chroma()
  vc1dec: Factorize picture pointer selection in vc1_mc_4mv_chroma()
  vc1dec: Factorize picture pointer selection code
  vc1dec: Factorize srcU/V offseting
  vc1dec: Fix tff == 0 handling in init_block_index()
  vc1dec: Update destination pointers in context for fields

Conflicts:
	libavcodec/vc1.c
	libavcodec/vc1dec.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>