Add -Werror compile flag.

SConstruct

 # Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import os
 
 SOURCES=['theme_draw.cc', 'theme_main.cc']
 
 env = Environment(
     CPPPATH=[ '..' ],
     CCFLAGS=['-g'],
 )
 
 for key in Split('CC CXX AR RANLIB LD NM CFLAGS CCFLAGS'):
   value = os.environ.get(key)
   if value != None:
     env[key] = Split(value)
-env['CCFLAGS'] += ['-fPIC', '-fno-exceptions', '-Wall']
+env['CCFLAGS'] += ['-fPIC', '-fno-exceptions', '-Wall', '-Werror']
 
 # Fix issue with scons not passing some vars through the environment.
 for key in Split('PKG_CONFIG_LIBDIR PKG_CONFIG_PATH SYSROOT'):
   if os.environ.has_key(key):
     env['ENV'][key] = os.environ[key]
 
 env.ParseConfig('pkg-config --cflags --libs gtk+-2.0 glib-2.0')
 
 env.SharedLibrary('theme', SOURCES)