build: Add separate hidden config option for the intrax8 code

This allows for slightly cleaner dependency specification.
x86: dsputil: Simplify xvmc deprecation conditional
Merge commit 'dc4d726bab59f349d366916ba01df16289e5c81f'

* commit 'dc4d726bab59f349d366916ba01df16289e5c81f':
  build: Add separate hidden config option for the intrax8 code

Conflicts:
	libavcodec/Makefile

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge remote-tracking branch 'qatar/master'

* qatar/master:
  x86: dsputil: Simplify xvmc deprecation conditional

Conflicts:
	libavcodec/x86/dsputil_init.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
fate: add WebP Exif metadata test

Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>