Add copyright headers to remaining gyp files.

gyp/nanomsg.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.
 {
   'variables': {
     'skia_warnings_as_errors': 0,
   },
   'targets': [{
     # Draws pictures cross-process.
     'target_name': 'nanomsg_picture_demo',
     'type': 'executable',
     'dependencies': [
       'skia_lib.gyp:skia_lib',
@@ skipping 190 matching lines @@
           'NN_USE_IFADDRS',
           'NN_USE_KQUEUE',
           'NN_USE_PIPE',
           'STDC_HEADERS',
           '_THREAD_SAFE',
         ],
       }],
     ]
   }]
 }