Merged from trunk 8729:8754

   Merged from trunk 8729:8754

   | 8731    | If portage is reinstalling itself, create a temporary copy   |
   | zmedico | of PORTAGE_BIN_PATH in order to avoid relying on on the new  |
   |         | versions which may be incompatible.                          |

   | 8732    | Enable the EBUILD_EXIT_STATUS_FILE sanity check when portage |
   | zmedico | is reinstalling itself since the check is reliable in this   |
   |         | case now that a temporary PORTAGE_BIN_PATH is created.       |

   | 8733    | Fix references to PORTAGE_BIN_PATH in doebuild() to use the  |
   | zmedico | config setting since it may be a temp directory when portage |
   |         | is reinstalling itself.                                      |

   | 8734    | In doebuild, fix paths to ebuild.sh and misc-functions.sh so |
   | zmedico | that they work with variable PORTAGE_BIN_PATH.               |

   | 8735    | Fix more references to MISC_SH_BINARY so that they work      |
   | zmedico | properly with variable PORTAGE_BIN_PATH.                     |

   | 8736    | Fix a typo.                                                  |
   | zmedico |                                                              |

   | 8737    | Make dblink.treewalk() properly delete the installed         |
   | zmedico | instance after it unmerges it.                               |

   | 8738    | Fix references to EBUILD_SH_BINARY so that they work         |
   | zmedico | properly with variable PORTAGE_BIN_PATH.                     |

   | 8739    | Remove stray print statement.                                |
   | zmedico |                                                              |

   | 8741    | In dblink.treewalk(), make portage unmerge multiple          |
   | zmedico | instances os sys-apps/portage in the same slot if necessary  |
   |         | (needed when AUTOCLEAN=no is set).                           |

   | 8743    | When portage reinstalls itself, copy both the bin and pym    |
   | zmedico | directories to a temp dir. Insert the temporary              |
   |         | PORTAGE_PYM_PATH as the first element of sys.path and        |
   |         | register an atexit hook to clean up the temporary            |
   |         | directories.                                                 |

   | 8745    | Adjust PYTHONPATH when calling portageq so that variable     |
   | zmedico | PORTAGE_PYM_PATH works.                                      |

   | 8747    | Don't modify sys.path inside dblink.merge() because it       |
   | zmedico | doesn't seem to help and it triggers import errors for elog  |
   |         | modules when downgrading to versions of portage that use the |
   |         | old namespace.                                               |

   | 8749    | When portage reinstalls itself, pre-load elog modules in     |
   | zmedico | dblink.merge() since we won't be able to later if they get   |
   |         | unmerged (happens when namespace changes).                   |

   | 8751    | Make elog_process() pre-load log modules that it can be      |
   | zmedico | called just for that purpose.                                |

   | 8753    | Move environment.bz2 extraction from ebuild.sh to doebuild() |
   | zmedico | on the python side. The python will be able to use it's      |
   |         | awareness of the ${T}/environment to decide what type of     |
   |         | ebuild environment should be generated. For example, if the  |
   |         | ebuild environment should be able to unset variables that    |
   |         | have been inherited from the calling environment, the        |
   |         | existence of ${T}/environment will indicate that the ebuild  |
   |         | environment should be isolated from the calling environment. |

   | 8754    | Bug #189417 - When ${T}/environment exists, isolate the      |
   | zmedico | ebuild environment from the calling environment. This makes  |
   |         | it possible for the build to unset a variable that was       |
   |         | inherited from the calling environment, and the variable     |
   |         | will remain unset between phases.                            |

svn path=/main/branches/prefix/; revision=8812