Merged from trunk -r13244:13253

   Merged from trunk -r13244:13253

   | 13245   | Add support for --rdeps-only and --root-deps options which   |
   | zmedico | are useful in combination with $ROOT. Thanks to Ned Ludd     |
   |         | <solar@g.o> for the initial patch.                           |

   | 13246   | Add a --root option that sets $ROOT (complements the         |
   | zmedico | --config-root option).                                       |

   | 13247   | Document --root and --config-root.                           |
   | zmedico |                                                              |

   | 13248   | Inside depgraph.validate_blockers(), prevent false positives |
   | zmedico | in PROVIDE virtual blocker matches that can occur for        |
   |         | packages for packages that don't actual have the appropriate |
   |         | value in PROVIDE (triggered by profile 'virtuals' settings). |
   |         | Thanks to Ned Ludd <solar@g.o> for reporting.                |

   | 13249   | Fix bug in old-style virtuals code from previous commit.     |
   | zmedico |                                                              |

   | 13250   | Update dep_getusedeps() docstring. Thanks to Douglass        |
   | zmedico | Anderson <dja@gendja.com>.                                   |

   | 13251   | Implement _use_dep.__repr__(). Thanks to Douglass Anderson   |
   | zmedico | for the suggestion.                                          |

   | 13252   | Bug #264291 - Fix inappropriate build dir creation for       |
   | zmedico | emerge --fetchonly.                                          |

   | 13253   | Fix --newuse code to compare installed package USE to the    |
   | zmedico | USE that a binary package was built with (instead of         |
   |         | config["PORTAGE_USE"]).                                      |

svn path=/main/branches/prefix/; revision=13276