Enable C++11 mode for iOS

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index d39128b1e23488a54a4aa840dd5caf5af1b20df6..79506d6439f73e2e3785a1cbb87e679d94865f25 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -3812,6 +3812,9 @@
           # but keying off (or setting) 'clang' isn't valid for iOS as it
           # also seems to mean using the custom build of clang.
 
+          # TODO(stuartmorgan): switch to c++0x (see TODOs in the clang
+          # section above).
+          'CLANG_CXX_LANGUAGE_STANDARD': 'gnu++0x',

[qsr, 2013/04/10 13:45:33]

How do we plan to be notified when we need to change this part of the
configuration? Should you modify the other TODO to have whoever changing the
other one also do the change here?

           # Don't use -Wc++0x-extensions, which Xcode 4 enables by default
           # when building with clang. This warning is triggered when the
           # override keyword is used via the OVERRIDE macro from
@@ -3829,9 +3832,9 @@
             '-Wno-unused-function',
             # See comments on this flag higher up in this file.
             '-Wno-unnamed-type-template-args',
-            # This (rightfully) complains about 'override', which we use
-            # heavily.
-            '-Wno-c++11-extensions',
+            # Match OS X clang C++11 warning settings.
+            '-Wno-c++11-narrowing',
+            '-Wno-reserved-user-defined-literal',
           ],
         },
         'target_conditions': [