Fixing some warnings on Linux

gyp/jsoncpp.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.
 
 # TODO: This file was copied from the external dependency
 # third_party/externals/jsoncpp-chromium/jsoncpp.gyp , at revision 125399,
 # with directory paths modified to work at this level.
 #
 # It would be better for us to depend on that gypfile within the external
 # dependency, but so far we have been unable to make that work reliably.
@@ skipping 49 matching lines @@
               'WarnAsError': 'false',
             },
           },
         }],
         [ 'skia_os == "android"', {
           'cflags!': [
             '-Wall',
             '-Werror',
           ],
         }],
+        ['skia_os in ["linux", "freebsd", "openbsd", "solaris", "nacl"]', {
+          'cflags!': [
+            '-Werror',
+          ],
+        }],
       ],
     },
   ],
 }
 
 # Local Variables:
 # tab-width:2
 # indent-tabs-mode:nil
 # End:
 # vim: set expandtab tabstop=2 shiftwidth=2: