Merge remote-tracking branch 'qatar/master'

* qatar/master:
  Remove some unused scripts from tools/.
  Add x86 assembly for some 10-bit H.264 intra predict functions.
  v4l2: do not force NTSC as standard
  Skip tableprint.h during 'make checkheaders'.
  Remove unnecessary LIBAVFORMAT_BUILD #ifdef.
  Drop explicit filenames from @file Doxygen tags.
  Skip generated table headers during 'make checkheaders'.
  lavf,lavc: free avoptions in a generic way.
  AVOptions: add av_opt_free convenience function.
  tableprint: Restore mistakenly deleted common.h #include for FF_ARRAY_ELEMS.
  tiff: print log in case of unknown / unsupported tag.
  tiff: fix linesize for mono-white/black formats.
  Fix build of eval-test program
  configure: Document --enable-vaapi
  ac3enc: extract all exponents for the frame at once

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

configure

@@ -106,7 +106,7 @@ Configuration options:
   --disable-lpc            disable LPC code
   --disable-mdct           disable MDCT code
   --disable-rdft           disable RDFT code
-  --disable-vaapi          disable VAAPI code
+  --enable-vaapi           enable VAAPI code
   --disable-vdpau          disable VDPAU code
   --disable-dxva2          disable DXVA2 code
   --enable-runtime-cpudetect detect cpu capabilities at runtime (bigger binary)