Merged from trunk -r14018:14028

   Merged from trunk -r14018:14028

   | 14019   | Create portage._merge_encoding and a corresponding _os_merge |
   | zmedico | wrapper that will later be used for all the merge code.      |

   | 14020   | Use portage's selinux wrapper module for mkdir calls.        |
   | zmedico |                                                              |

   | 14021   | Make _ensure_default_encoding() provide a fallback for the   |
   | zmedico | codec returned by sys.getfilesystemencoding().               |

   | 14022   | Replace the selinux.spawn() function with a spawn_wrapper()  |
   | zmedico | function and use it inside portage._spawn_fetch() and        |
   |         | portage.spawn().                                             |

   | 14023   | Don't use the unicode-wrapped os and shutil modules here     |
   | zmedico | since the whole _selinux module itself will be wrapped.      |

   | 14024   | Add an 'encoding' parameter to movefile(), so that we can    |
   | zmedico | make it obey sys.getfilesystemencoding() when called for     |
   |         | merge/unmerge.                                               |

   | 14025   | Make sure portage.selinux and _selinux exist, even when      |
   | zmedico | import fails, so that 'from portage import selinux' never    |
   |         | fails inside vartree.py.                                     |

   | 14026   | Don't 'del sys.modules["selinux"]' when selinux support      |
   | zmedico | isn't enabled in the portage config, because that just       |
   |         | assumes too much.                                            |

   | 14027   | Use portage._merge_encoding to encode/decode all filenames   |
   | zmedico | during merge/unmerge operations.                             |

   | 14028   | _merge_encoding = sys.getfilesystemencoding()                |
   | zmedico |                                                              |

svn path=/main/branches/prefix/; revision=14046