message: Remove libmp4v2 libopenssl and libsrtp include dirs if external mediaserver is used and add new LIBMEDIASERVER_INCLUDE env variable
diff: 'variables':
  {
  'external_libmediaserver%' : '<!(echo $LIBMEDIASERVER)',
  + 'external_libmediaserver_include_dirs%' : '<!(echo $LIBMEDIASERVER_INCLUDE)',
  },
  "targets":
  [
  ],
  "include_dirs" :
  [
  - 'external/mp4v2/lib/include',
  - 'external/mp4v2/config/include',
  - 'external/srtp/include',
  - 'external/openssl/lib/include',
  - 'media-server/include',
  - 'media-server/src',
  '/usr/include/nodejs/',
  "<!(node -e \"require('nan')\")"
  ],
  [
  "external_libmediaserver == ''",
  {
  + "include_dirs" :
  + [
  + 'media-server/include',
  + 'media-server/src',
  + 'external/mp4v2/lib/include',
  + 'external/mp4v2/config/include',
  + 'external/srtp/include',
  + 'external/openssl/lib/include',
  + ],
  "sources":
  [
  "media-server/src/RTPBundleTransport.cpp",
  },
  {
  "libraries" : [ "<(external_libmediaserver)" ]
  + "include_dirs" : [ "<(external_libmediaserver_include_dirs)" ]
  }
  ]
  ]
  