Cross-compiling from Linux to Android requires -lrt for the host toolset.

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.
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@@ skipping 704 matching lines @@
                     'sources': [
                       '../../src/platform-macos.cc'
                     ]
                   }, {
                     'sources': [
                       '../../src/platform-linux.cc'
                     ]
                   }],
                 ],
               }, {
+                'link_settings': {
+                  'target_conditions': [

[yurys, 2013/08/28 14:08:34]

Will it work on Mac OS X?

[Benedikt Meurer, 2013/08/28 14:10:08]

Yes, Mac OS X uses mach_absolute_time() instead of clock_gettime() and there's
no -lrt nor clock_gettime() in OS X, so we don't need to care about linking to
librt. Android itself has clock_gettime() in libc.

+                    ['_toolset=="host"', {
+                      'libraries': [
+                        '-lrt'
+                      ]
+                    }]
+                  ]
+                },
                 'sources': [
                   '../../src/platform-linux.cc'
                 ]
               }],
             ],
           },
         ],
         ['OS=="freebsd"', {
             'link_settings': {
               'libraries': [
@@ skipping 304 matching lines @@
         }],
         ['v8_compress_startup_data=="bz2"', {
           'libraries': [
             '-lbz2',
           ]
         }],
       ],
     },
   ],
 }