linux: don't make -Werror setting conditional on OS

build/common.gypi

 # 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.
 
 # 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 1636 matching lines @@
         }],
       ],
     },
   },
   'conditions': [
     ['os_posix==1 and OS!="mac"', {
       'target_defaults': {
         # Enable -Werror by default, but put it in a variable so it can
         # be disabled in ~/.gyp/include.gypi on the valgrind builders.
         'variables': {
-          'conditions': [
-            ['OS=="linux"', {
-              'werror%': '-Werror',
-              }, { # turn off -Werror on other Unices
-              'werror%': '',
-            }],
-          ],
+          'werror%': '-Werror',
         },
         'cflags': [
           '<(werror)',  # See note above about the werror variable.
           '-pthread',
           '-fno-exceptions',
           '-fno-strict-aliasing',  # See http://crbug.com/32204
           '-Wall',
           # TODO(evan): turn this back on once all the builds work.
           # '-Wextra',
           # Don't warn about unused function params.  We use those everywhere.
@@ skipping 1129 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',
   },
 }