Fix for missing file from previous CL that broke the build.

The file defines skia_target_arch to '' for non-arm platforms.

git-svn-id: http://skia.googlecode.com/svn/trunk@2593 2bbb7eff-a529-9590-31e7-b0007b416f81

gyp/common_variables.gypi

@@ -10,10 +10,12 @@
     'skia_scalar%': 'float',
     'skia_os%': '<(OS)',
     'skia_mesa%': 0,
+    'skia_target_arch%': '',
   },
   'skia_scalar%': '<(skia_scalar)',
   'skia_os': '<(skia_os)',
   'skia_mesa': '<(skia_mesa)',
+  'skia_target_arch': '<(skia_target_arch)',
 }
 
 # Local Variables: