Add SkPreConfig.h to core.gypi

BUG=
R=reed@google.com

Author: borenet@google.com

Review URL: https://codereview.chromium.org/116903007

git-svn-id: http://skia.googlecode.com/svn/trunk@12886 2bbb7eff-a529-9590-31e7-b0007b416f81

gyp/core.gypi

@@ -268,6 +268,7 @@
         '<(skia_include_path)/core/SkPicture.h',
         '<(skia_include_path)/core/SkPixelRef.h',
         '<(skia_include_path)/core/SkPoint.h',
+        '<(skia_include_path)/core/SkPreConfig.h',
         '<(skia_include_path)/core/SkRasterizer.h',
         '<(skia_include_path)/core/SkReader32.h',
         '<(skia_include_path)/core/SkRect.h',