use SK_ScalarPI, and fix ARM build

git-svn-id: http://skia.googlecode.com/svn/trunk/gyp@10212 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/opts.gyp b/opts.gyp
index bcc85a9..c15cfb6 100644
--- a/opts.gyp
+++ b/opts.gyp
@@ -96,6 +96,7 @@
         [ '(skia_arch_type == "arm" and armv7 == 0) or (skia_os == "ios")', {
           'sources': [
             '../src/opts/SkBitmapProcState_opts_none.cpp',
+            '../src/opts/SkBitmapFilter_opts_none.cpp',
             '../src/opts/SkBlitRow_opts_none.cpp',
             '../src/opts/SkUtils_opts_none.cpp',
           ],