mac: Turn on partial availability warning.

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 2549 matching lines @@
         # this is worth fixing.
         '-Wno-c++11-narrowing',
 
         # Clang considers the `register` keyword as deprecated, but e.g.
         # code generated by flex (used in angle) contains that keyword.
         # http://crbug.com/255186
         '-Wno-deprecated-register',
 
         # TODO(hans): Get this cleaned up.
         '-Wno-inconsistent-missing-override',
+
+        # When compiling Objective C, warns if a method is used whose
+        # availability is newer than the deployment target.
+        '-Wpartial-availability',

[Nico, 2015/05/19 00:58:20]

We probably want to do this in some OS==mac section so that it isn't set for iOS
– this would confuse Xcode's clang and is probably not desired for iOS builds
with chromium's clang either

(also not needed on linux and windows where it won't do anything)

[erikchen, 2015/05/19 01:32:21]

Ah - hadn't considered the effect on iOS. Done.

       ],
     },
     'includes': [ 'set_clang_warning_flags.gypi', ],
     'defines': [
       # Don't use deprecated V8 APIs anywhere.
       'V8_DEPRECATION_WARNINGS',
     ],
     'include_dirs': [
       '<(SHARED_INTERMEDIATE_DIR)',
     ],
@@ skipping 3606 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',
   },
 }