linux: ignore warnings about unused results in third-party code

build/common.gypi

 # Copyright (c) 2011 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 861 matching lines @@
               '-Wall',
               '-Wextra',
               '-Werror',
             ],
             'cflags': [
               # Don't warn about hash_map in third-party code.
               '-Wno-deprecated',
               # Don't warn about printf format problems.
               # This is off by default in gcc but on in Ubuntu's gcc(!).
               '-Wno-format',
+              # Don't warn about ignoring the return value from e.g. close().
+              # This is off by default in some gccs but on by default in others.
+              '-Wno-unused-result',
             ],
             'cflags_cc!': [
               # TODO(fischman): remove this.
               # http://code.google.com/p/chromium/issues/detail?id=90453
               '-Wsign-compare',
             ]
           }],
           [ 'OS=="win"', {
             'defines': [
               '_CRT_SECURE_NO_DEPRECATE',
@@ skipping 12 matching lines @@
           }],
           # TODO(darin): Unfortunately, some third_party code depends on base/
           [ 'OS=="win" and component=="shared_library"', {
             'msvs_disabled_warnings': [
               4251,  # class 'std::xx' needs to have dll-interface.
             ],
           }],
           [ 'OS=="mac"', {
             'xcode_settings': {
               'GCC_TREAT_WARNINGS_AS_ERRORS': 'NO',
               'WARNING_CFLAGS!': ['-Wall', '-Wextra'],

[Nico, 2011/07/26 21:46:48]

Add here as well (in a 'WARNING_CFLAGS' block without the !)

[Evan Martin, 2011/07/26 21:54:07]

I don't see this warning in the mac build logs.  Maybe it's from a different
version of gcc?

[Ami GONE FROM CHROMIUM, 2011/07/26 21:59:38]

mac builders use gcc 4.2?

[Nico, 2011/07/26 22:04:43]

I tried to look on the clang bots but couldn't find a recent clobber build.

Ok.

             },
           }],
         ],
       }, {
         # In Chromium code, we define __STDC_FORMAT_MACROS in order to get the
         # C99 macros on Mac and Linux.
         'defines': [
           '__STDC_FORMAT_MACROS',
         ],
         'conditions': [
@@ skipping 963 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }