Merged from trunk -r12583:12593

   Merged from trunk -r12583:12593

   | 12584    | For python-3.0 compatibility, make dict-like classes modify |
   | zmedico  | their keys(), items(), and values() methods appropriatly    |
   |          | for the current python version.                             |

   | 12585    | Inside depgraph._serialize_tasks(), simplify the logic      |
   | zmedico  | which delays selection of root nodes.                       |

   | 12586    | Make DepPriority.__str__() indicate optional deps.          |
   | zmedico  |                                                             |

   | 12587    | Fix digraph.clone() to properly clone priority lists.       |
   | zmedico  |                                                             |

   | 12588    | fix --libdir detection when econf is passed                 |
   | SpankMan | whitespace/empty arguments ... those break the plain string |
   |          | expansion comparison                                        |

   | 12589    | fix previous commit -- hasq isnt as cool as i thought and   |
   | SpankMan | doesnt accept globs, so define a new hasg() func that does  |
   |          | and use that                                                |

   | 12590    | cleanup econf() code -- use hasg* funcs in multilib code to |
   | SpankMan | avoid wrong/duplicate parsing methods, move all handling to |
   |          | "$@" to avoid duplication, and make sure we prepend         |
   |          | arguments coming from the ebuild rather than append -- only |
   |          | EXTRA_ECONF from user should override things                |

   | 12591    | Escape globs in hasgq arguments in order to prevent bash    |
   | zmedico  | from trying to perform filename expansion.                  |

   | 12592    | Filter the new hasg and hasgq functions inside              |
   | zmedico  | save_ebuild_env().                                          |

   | 12593    | add support for .xz compressed files like .lzma             |
   | SpankMan |                                                             |

svn path=/main/branches/prefix/; revision=12607