Add OPT=1 flag to build optimized on Linux.

third_party/dmg_fp/dmg_fp.scons

 # Copyright (c) 2008 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.
 
 Import('env')
 
 env = env.Clone()
 
 # Do *NOT* define USE_LOCALE here. We want these functions to be
 # locale-independent, for example to use in parsers or serializers.
@@ skipping 13 matching lines @@
           '/wd4800',
           '/wd4819',
       ],
   )
 
 if env['PLATFORM'] in ('darwin', 'posix'):
   # As usual with third party code, it generates lots of warnings.
   # Disable only what's necessary.
   env.Append(
       CCFLAGS = [
+          '-Wno-uninitialized',
           '-Wno-parentheses',
           '-Wno-sign-compare',
           '-Wno-unused-label',
           '-Wno-write-strings',
       ]
   )
 
 input_files = [
     'dtoa.cc',
     'g_fmt.cc',
 ]
 
 env.ChromeStaticLibrary('dmg_fp', input_files)