One more step towards working Mac SCons build....

third_party/zlib/zlib.scons

 # Copyright (c) 2006-2008 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.
 
 __doc__ = """
 Configuration for building zlib.lib / libzlib.a.
 """
 
 Import('env')
 
@@ skipping 45 matching lines @@
     'contrib/minizip/unzip.c',
     'contrib/minizip/unzip.h'
 ])
 
 if env.Bit('windows'):
   input_files.extend([
       'contrib/minizip/iowin32.c',
       'contrib/minizip/iowin32.h',
   ])
 
+if env.Bit('posix'):
+  env.Append(
+      CCFLAGS = [
+          '-Wno-parentheses',
+          '-Wno-unused-variable',
+      ],
+  )
+
 env.ChromeLibrary('zlib', input_files)
 
 p = env.ChromeMSVSProject('zlib.vcproj',
                           guid='{8423AF0D-4B88-4EBF-94E1-E4D00D00E21C}',
                           files=input_files,
                           relative_path_prefix=r'./',
                           tools = [
                               'VCLibrarianTool',
                               'VCCLCompilerTool',
                           ])
@@ skipping 14 matching lines @@
                 '$(SolutionDir)../build/release.vsprops',
                 '$(SolutionDir)../build/external_code.vsprops',
                 './zlib.vsprops'
             ])
 
 env.AlwaysBuild(p)
 
 i = env.Command('$CHROME_SRC_DIR/third_party/zlib/zlib.vcproj', p,
                 Copy('$TARGET', '$SOURCE'))
 Alias('msvs', i)