Work-around missing librt for cross-compiling Chrome for Android in AOSP.

tools/gyp/v8.gyp

 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 706 matching lines @@
                     'sources': [
                       '../../src/platform-macos.cc'
                     ]
                   }, {
                     'sources': [
                       '../../src/platform-linux.cc'
                     ]
                   }],
                 ],
               }, {
-                'link_settings': {
-                  'target_conditions': [
-                    ['_toolset=="host"', {
-                      'libraries': [
-                        '-lrt'
-                      ]
-                    }]
-                  ]
-                },
+                # TODO(bmeurer): What we really want here, is this:
+                #
+                # 'link_settings': {
+                #   'target_conditions': [
+                #     ['_toolset=="host"', {
+                #       'libraries': [
+                #         '-lrt'
+                #       ]
+                #     }]
+                #   ]
+                # },
+                #
+                # but we can't do this right now, as the AOSP does not support
+                # linking against the host librt, so we need to work around this
+                # for now, using the following hack (see platform/time.cc):
+                'target_conditions': [
+                  ['_toolset=="host"', {
+                    'defines': [
+                      'V8_LIBRT_NOT_AVAILABLE',
+                    ],
+                  }],
+                ],
                 'sources': [
                   '../../src/platform-linux.cc'
                 ]
               }],
             ],
           },
         ],
         ['OS=="freebsd"', {
             'link_settings': {
               'libraries': [
@@ skipping 304 matching lines @@
         }],
         ['v8_compress_startup_data=="bz2"', {
           'libraries': [
             '-lbz2',
           ]
         }],
       ],
     },
   ],
 }