Merged from trunk -r15360:15370

   Merged from trunk -r15360:15370

   | 15361   | Fix type in CLEAN_DELAY docs.                                |
   | zmedico |                                                              |

   | 15362   | Bug #303567 - Merge libc asap, in order to account for       |
   | zmedico | implicit dependencies.                                       |

   | 15363   | Add @rebuilt-binaries set which uses BUILD_TIME to pull in   |
   | zmedico | binary packages that have a different build time from a      |
   |         | currently installed package of the exact same version.       |

   | 15364   | Add a --rebuilt-binaries[=n] option, causing automatic       |
   | zmedico | replacement of installed packages with binary packages that  |
   |         | have been rebuilt. Rebuilds are detected by comparison of    |
   |         | BUILD_TIME package metadata. This option is enabled          |
   |         | automatically when using binary packages, so rebuilt         |
   |         | binaries are installed with a user's typical update command. |
   |         | This isn't possible with the existing @rebuild-binaries      |
   |         | package set since that only works with --selective=n and     |
   |         | therefore can't be used with a typical world update. The     |
   |         | package set framework should support this type of behavior   |
   |         | sometime in the future.                                      |

   | 15365   | Bug #305393 - Handle new sdiff exit status for               |
   | zmedico | diffutils-2.9.                                               |

   | 15366   | Add a comment about slowness in _serialize_tasks when there  |
   | zmedico | are lots of blockers to solve.                               |

   | 15367   | Fix colors for --rebuilt-binaries docs.                      |
   | zmedico |                                                              |

   | 15368   | Fix broken diffutils vercmp code.                            |
   | zmedico |                                                              |

   | 15369   | Update the spinner in depgraph._serialize_tasks when         |
   | zmedico | searching for suitable uninstall tasks.                      |

   | 15370   | Remove diffutils version detection code since it's not       |
   | zmedico | really needed.                                               |

svn path=/main/branches/prefix/; revision=15386