Add some more libjingle targets to the GN build.

third_party/usrsctp/usrsctp.gyp

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 {
   'variables': {
     'libsctp_target_type%': 'static_library',
   },
   'target_defaults': {
     'defines': [
       'SCTP_PROCESS_LEVEL_LOCKS',
@@ skipping 35 matching lines @@
               '<(DEPTH)/third_party/nss/nss.gyp:nspr',
               '<(DEPTH)/third_party/nss/nss.gyp:nss',
             ],
           }],
         ],
       }],
     ],
   },
   'targets': [
     {
+      # GN version: //third_party/usrsctp
       'target_name': 'usrsctplib',
       'type': 'static_library',
       'sources': [
+        # Note: sources list duplicated in GN build.
         'usrsctplib/netinet/sctp.h',
         'usrsctplib/netinet/sctp_asconf.c',
         'usrsctplib/netinet/sctp_asconf.h',
         'usrsctplib/netinet/sctp_auth.c',
         'usrsctplib/netinet/sctp_auth.h',
         'usrsctplib/netinet/sctp_bsd_addr.c',
         'usrsctplib/netinet/sctp_bsd_addr.h',
         'usrsctplib/netinet/sctp_callout.c',
         'usrsctplib/netinet/sctp_callout.h',
         'usrsctplib/netinet/sctp_cc_functions.c',
@@ skipping 95 matching lines @@
           'msvs_disabled_warnings': [ 4002, 4013, 4018, 4133, 4267, 4313, 4700 ],
         }, {  # OS != "win",
           'defines': [
             'NON_WINDOWS_DEFINE',
           ],
         }],
       ],  # conditions
     },  # target usrsctp
   ],  # targets
 }