Add copyright headers to remaining gyp files.

gyp/opts.gyp

+# Copyright 2015 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
 # Gyp file for building opts target.
 {
   # Source lists live in opts.gypi.  This makes it easier to maintain our Chrome GYP/GN setup.
   # (To be honest, I'm not sure why we need to include common.gypi.  I thought it was automatic.)
   'variables': {
     'includes': [ 'common.gypi', 'opts.gypi' ],
   },
 
   # Generally we shove things into one 'opts' target conditioned on platform.
   # If a particular platform needs some files built with different flags,
@@ skipping 140 matching lines @@
           ],
         }],
       ],
       'ldflags': [
         '-march=armv7-a',
         '-Wl,--fix-cortex-a8',
       ],
     },
   ],
 }