Change-Id: Ib19dabe697656e4d7e8403d91bedca7cd31d36bf

apparently we are going to have trouble completely removing lint issue in this file.
It needs a bit more work.   We need to include vpx_config.h to know whether
we need to have multi threading .    and that means vpx_config.h has to come
before the system headers.  ( a violation )

Change-Id: I023feeab1bf5643b79dccc3b80a4a9ad42689e7b
Signed-off-by: Jim Bankoski <jimbankoski@google.com>

vp9/decoder/vp9_thread.[hc]
Original source:
 http://git.chromium.org/webm/libwebp.git
 100644 blob b1615d0fb8d311666b2fa4561076c62d72c2e3ff  src/utils/thread.c
 100644 blob 13a61a4c84194c3374080cbf03d881d3cd6af40d  src/utils/thread.h

Local modifications:
 - s/WebP/VP9/g
 - camelcase functions -> lower with _'s

Change-Id: Ib6932640ee34f8b4782c6fbd15864a59d5d4c5fe