Merged from trunk 8661:8696

   Merged from trunk 8661:8696

   | 8662    | Remove some unsafe assumptions from preprocess_ebuild_env()  |
   | zmedico | and note the remaining assumption that save_ebuild_env() is  |
   |         | not overridden by the environment being loaded.              |

   | 8663    | Make preprocess_ebuild_env() reload a known good version of  |
   | zmedico | save_ebuild_env() in order to avoid making an assumption     |
   |         | that it hasn't been overridden.                              |

   | 8666    | Filter _RC_GET_KV_CACHE from the saved environment.          |
   | zmedico |                                                              |

   | 8668    | Bug #124041 - Make emerge show an informative warning        |
   | zmedico | message when one or more eclasses override eclasses from     |
   |         | PORTDIR. The warning can be permanently disabled by setting  |
   |         | PORTAGE_ECLASS_WARNING_ENABLE="0" in /etc/make.conf.         |

   | 8670    | * Move filtering of a bunch of portage config variables from |
   | zmedico | save_ebuild_env() to config.environ(). * Add EMERGE_FROM to  |
   |         | the READONLY_PORTAGE_VARS list.                              |

   | 8672    | Add NOCONFMEM to config._environ_filter.                     |
   | zmedico |                                                              |

   | 8674    | unset ECLASS along with the other variables from inherit().  |
   | zmedico |                                                              |

   | 8676    | Filter more misc environment variables.                      |
   | zmedico |                                                              |

   | 8678    | Make diefunc() show the path of ${T}/environment since it's  |
   | zmedico | usually in the stack trace and the user is likely to be      |
   |         | interested in it.                                            |

   | 8680    | Automatically try to load environment.bz2 whenever           |
   | zmedico | "${T}/environment" does not exist, except for "clean" and    |
   |         | "depend" phases.                                             |

   | 8682    | Bug #200313 - Detect and report when an ebuild phase exits   |
   | zmedico | unexpectedly. This is type of behavior is known to be        |
   |         | triggered by things such as failed variable assignments (bug |
   |         | #190128) or bad substitution errors (bug #200313). We use a  |
   |         | EBUILD_EXIT_STATUS_FILE environment variable to specify a    |
   |         | file that the shell code is supposed to create when it exits |
   |         | in a normal manner. If the file does not get created like    |
   |         | it's supposed to be then we can conclude that the shell has  |
   |         | exited in some unexpected way.                               |

   | 8683    | --buildpkgonly will not merge anything, so it cancels all    |
   | zmedico | binary package options.                                      |

   | 8686    | Check if ${EBUILD_EXIT_STATUS_FILE} is empty before          |
   | zmedico | attempting to use it.                                        |

   | 8688    | Implement config.pop().                                      |
   | zmedico |                                                              |

   | 8690    | Make config.pop() properly call config.modifying().          |
   | zmedico |                                                              |

   | 8692    | * In doebuild(), don't create directories for the "clean" or |
   | zmedico | "unmerge". * Fix dyn_clean() to clean the status file and    |
   |         | return early when appropriate.                               |

   | 8694    | Fix grammar.                                                 |
   | zmedico |                                                              |

   | 8696    | Make doebuild skip directory creation for the "cleanrm"      |
   | zmedico | command.                                                     |

svn path=/main/branches/prefix/; revision=8809