Refactor how clang warning flags are set.

third_party/libxml/libxml.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.
 
 {
   'variables': {
     'conditions': [
       # Define an "os_include" variable that points at the OS-specific generated
       # headers.  These were generated by running the configure script offline.
       ['os_posix == 1 and OS != "mac" and OS != "ios"', {
@@ skipping 170 matching lines @@
             'win32/config.h',
             'win32/include/libxml/xmlversion.h',
           ],
           'defines': [
             # Define LIBXML_STATIC as nothing to match how libxml.h
             # (an internal header) defines LIBXML_STATIC, otherwise
             # we get the macro redefined warning from GCC.  (-DFOO
             # defines the macro FOO as 1.)
             'LIBXML_STATIC=',
           ],
+          'variables': {
+            'clang_warning_flags': [
+              # libxml passes `const unsigned char*` through `const char*`.
+              '-Wno-pointer-sign',
+              # pattern.c and uri.c both have an intentional
+              # `for (...);` / `while(...);` loop. I submitted a patch to
+              # move the `'` to its own line, but until that's landed
+              # suppress the warning:
+              '-Wno-empty-body',
+              # debugXML.c compares array 'arg' to NULL.
+              '-Wno-tautological-pointer-compare',
+              # See http://crbug.com/138571#c8
+              '-Wno-ignored-attributes',
+            ],
+          },
           'include_dirs': [
             '<(os_include)',
             '<(os_include)/include',
             'src/include',
           ],
           'dependencies': [
             '../icu/icu.gyp:icuuc',
             '../zlib/zlib.gyp:zlib',
           ],
           'export_dependent_settings': [
@@ skipping 26 matching lines @@
               'product_name': 'libxml2',
               # Disable unimportant 'unused variable' warning, and
               # signed/unsigned comparison warning. The signed/unsigned (4101)
               # is fixed upstream and can be removed eventually.
               # TODO(jschuh): http://crbug.com/167187 size_t -> int
               'msvs_disabled_warnings': [ 4018, 4101, 4267 ],
             }, {  # else: OS!="win"
               'product_name': 'xml2',
             }],
             ['clang==1', {
-              'xcode_settings': {
-                'WARNING_CFLAGS': [
-                  # libxml passes `const unsigned char*` through `const char*`.
-                  '-Wno-pointer-sign',
-                  # pattern.c and uri.c both have an intentional
-                  # `for (...);` / `while(...);` loop. I submitted a patch to
-                  # move the `'` to its own line, but until that's landed
-                  # suppress the warning:
-                  '-Wno-empty-body',
-                  # debugXML.c compares array 'arg' to NULL.
-                  '-Wno-tautological-pointer-compare',
-                ],
-              },
-              'cflags': [
-                '-Wno-pointer-sign',
-                '-Wno-empty-body',
-                '-Wno-tautological-pointer-compare',
-
-                # See http://crbug.com/138571#c8
-                '-Wno-ignored-attributes',
-              ],
               'msvs_settings': {
                 'VCCLCompilerTool': {
                   'AdditionalOptions': [
                     # VS2012's standard lib doesn't provide nan().
                     '/U__STDC_VERSION__',
                   ],
                 },
               },
             }],
           ],
         }],
       ],
     },
   ],
 }