Explicitly only use xmldummy_mac.cc on Mac systems, since libxml (as

third-party code) doesn't exclude _mac.cc files automatically.
BUG=none
TEST=build without warning
Review URL: http://codereview.chromium.org/194062

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@25818 0039d316-1c4b-4281-b951-d872f2087c98

third_party/libxml/libxml.gyp

@@ -189,7 +189,6 @@
       'type': 'executable',
       'sources': [
         'xmlcatalog.c',
-        'xmldummy_mac.cc',
       ],
       'include_dirs': [
         '<(os_include)',
@@ -206,6 +205,11 @@
             ],
           },
         }],
+        ['OS=="mac"', {
+          'sources': [
+            'xmldummy_mac.cc',
+          ],
+        }],
       ],
     },
     {
@@ -213,7 +217,6 @@
       'type': 'executable',
       'sources': [
         'xmllint.c',
-        'xmldummy_mac.cc',
       ],
       'include_dirs': [
         '<(os_include)',
@@ -231,6 +234,11 @@
             ],
           },
         }],
+        ['OS=="mac"', {
+          'sources': [
+            'xmldummy_mac.cc',
+          ],
+        }],
       ],
     },
   ],