Manually cherry-picked the following changes:
8c8d16de vp9 -> vpx in names
75b57d39 VP9_ -> VPX_ in function names
761a7088 VP9_INTERP_EXTEND -> VPX_INTERP_EXTEND
4273a52c VP9->VPX in border pixel macros
03568c31 VP9_FRAME_MARKER -> VPX_FRAME_MARKER
2334f51d VP9->VPX in fdct function names
Change-Id: Icc18dbf4b416dd0fa21033b3e19ab8a47c893508
MMX and X87 floating point instructions cannot be mixed freely on
the 32 bit x86 architecture.
This fixes a lot of unit tests in the 32bit build with
--enable-ext-intra.
BUG=https://bugs.chromium.org/p/webm/issues/detail?id=1196
Change-Id: I0e1c3565f4b9cb4fc2d716e94d9c40e68b36fac8
