Merged from trunk -r12380:12384

   Merged from trunk -r12380:12384

   | 12381   | Do not hardlink files unless they are in the same directory, |
   | zmedico | since otherwise tar may not be able to extract a tarball of  |
   |         | the resulting hardlinks due to 'Invalid cross-device link'   |
   |         | errors (depends on layout of mount points). Also, don't      |
   |         | hardlink zero-byte files since it doesn't save any space.    |
   |         | Thanks to Daniel Robbins for reporting these issues which    |
   |         | were noticed by funtoo users when attempting to extract      |
   |         | stage tarballs.                                              |

   | 12382   | Remove print statement from previous commit.                 |
   | zmedico |                                                              |

   | 12383   | Fix _setitem() to write the same format that's currently     |
   | zmedico | distributed in the rsync tree.                               |

   | 12384   | When the set configuration is incomplete, notify the user    |
   | zmedico | that this usually means /usr/share/portage/config/sets.conf  |
   |         | is missing or corrupt.                                       |

svn path=/main/branches/prefix/; revision=12395