Refactor how clang warning flags are set.

third_party/snappy/snappy.gyp

Index: third_party/snappy/snappy.gyp
diff --git a/third_party/snappy/snappy.gyp b/third_party/snappy/snappy.gyp
index da237009ef060d5bc2d983ea2be113f3d8f8b5c4..de055578f2a937149710a8aa05ba7dbc7a832f1f 100644
--- a/third_party/snappy/snappy.gyp
+++ b/third_party/snappy/snappy.gyp
@@ -30,6 +30,13 @@
           'src',
         ],
       },
+      'variables': {
+        'clang_warning_flags_unset': [
+          # snappy-stubs-internal.h unapologetically has: using namespace std
+          # https://code.google.com/p/snappy/issues/detail?id=70
+          '-Wheader-hygiene',
+        ],
+      },
       'sources': [
         'src/snappy-internal.h',
         'src/snappy-sinksource.cc',
@@ -40,14 +47,6 @@
         'src/snappy.h',
       ],
       'conditions': [
-        ['clang == 1', {
-          # snappy-stubs-internal.h unapologetically has: using namespace std
-          # https://code.google.com/p/snappy/issues/detail?id=70
-          'xcode_settings': {
-            'WARNING_CFLAGS!': [ '-Wheader-hygiene' ],
-          },
-          'cflags': [ '-Wno-header-hygiene' ],
-        }],
         ['OS=="linux" or OS=="mac"', {
           'defines': [
             # TODO(tfarina): Only Mac and Linux has the generated config.h for
@@ -81,6 +80,10 @@
         '../../testing/gtest.gyp:gtest',
         '../../third_party/zlib/zlib.gyp:zlib',
       ],
+      'variables': {
+        'clang_warning_flags': [ 'Wno-return-type' ],

[hans, 2014/08/01 21:23:29]

There's a dash missing here.

[Nico, 2014/08/01 21:25:06]

Hm, so I guess if this still gets green runs, this flag isn't needed? I'll try
removing it.

[Nico, 2014/08/01 21:35:20]

…looks like not bot builds this target. So I added the -, maybe someone uses
this target locally?

+        'clang_warning_flags_unset': [ '-Wheader-hygiene' ],
+      },
       'conditions': [
         ['OS=="linux" or OS=="mac"', {
           'defines': [
@@ -90,12 +93,6 @@
             'HAVE_CONFIG_H=1',
           ],
         }],
-        ['clang == 1', {
-          'cflags': [
-            '-Wno-return-type',
-            '-Wno-header-hygiene'
-          ],
-        }],
       ],
     },
   ],