Mac: clang build

Fixes the last few warnings / errors necessary to build chrome/mac with clang.

See http://code.google.com/p/chromium/wiki/Clang

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/2762014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@60131 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/build/common.gypi b/build/common.gypi
index d81c567..66294115 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -1234,6 +1234,13 @@
             ['chromium_mac_pch', {'GCC_PRECOMPILE_PREFIX_HEADER': 'YES'},
                                  {'GCC_PRECOMPILE_PREFIX_HEADER': 'NO'}
             ],
+            ['clang==1', {
+              'WARNING_CFLAGS': [
+                # Don't die on dtoa code that uses a char as an array index.
+                # This is required solely for base/third_party/dmg_fp/dtoa.cc.
+                '-Wno-char-subscripts',
+              ],
+            }],
           ],
         },
         'target_conditions': [