Define SK_CPU_X86 on x86 machines.

Use this to only register flattening for SkSSE2ProcCoeffXfermode::CreateProc when it's linked.

BUG=skia:

R=reed@google.com, mtklein@google.com, bsalomon@google.com
TBR=reed@google.com
NOTRY=true
NOTREECHECKS=true

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/231223002

git-svn-id: http://skia.googlecode.com/svn/trunk@14108 2bbb7eff-a529-9590-31e7-b0007b416f81
2 files changed