disable avx2 on linux
--enable-pic on osx in update.py
update.py fix 32bit builds
libvpx run update.py to fix 32bit builds
Merge remote-tracking branch 'open/vpx-1.3.0v5' into vpx-1.3.0v5
Merge remote-tracking branch 'open/vpx-1.3.0v5' into vpx-1.3.0v5