Add a system() call to the d8 shell (Unix only).

src/SConscript

 # Copyright 2008 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 65 matching lines @@
   'mode:debug': [
     'objects-debug.cc', 'prettyprinter.cc', 'regexp-macro-assembler-tracer.cc'
   ]
 }
 
 
 D8_FILES = {
   'all': [
     'd8.cc', 'd8-debug.cc'
   ],
+  'os:linux': [
+    'd8-posix.cc'
+  ],
+  'os:macos': [
+    'd8-posix.cc'
+  ],
+  'os:android': [
+    'd8-posix.cc'
+  ],
+  'os:freebsd': [
+    'd8-posix.cc'
+  ],
+  'os:windows': [
+    'd8-windows.cc'
+  ],
+  'os:nullos': [
+    'd8-windows.cc'   # Empty implementation at the moment.
+  ],
   'console:readline': [
     'd8-readline.cc'
   ]
 }
 
 
 LIBRARY_FILES = '''
 runtime.js
 v8natives.js
 array.js
@@ skipping 59 matching lines @@
     snapshot_obj = context.ConfigureObject(env, snapshot_cc, CPPPATH=['.'])
     libraries_obj = context.ConfigureObject(env, libraries_empty_src, CPPPATH=['.'])
   else:
     snapshot_obj = empty_snapshot_obj
   library_objs = [non_snapshot_files, libraries_obj, snapshot_obj]
   return (library_objs, d8_objs, [mksnapshot])
 
 
 (library_objs, d8_objs, mksnapshot) = ConfigureObjectFiles()
 Return('library_objs d8_objs mksnapshot')