Merged from trunk -r15815:15825

   Merged from trunk -r15815:15825

   | 15820   | Bug #309001 - Only trust tar exit status (ignore             |
   | zmedico | decompressor exit status) when unpacking tar files.          |

   | 15821   | Trust tar exit status and ignore bzip2 exit status as in bug |
   | zmedico | #309001.                                                     |

   | 15822   | Simplyfy the virtual.exists check, and avoid deprecation     |
   | zmedico | warning triggered by cpv_getkey called on an empty string.   |

   | 15823   | Bug #309001 - Use signal(signal.SIGPIPE, signal.SIG_DFL) for |
   | zmedico | quiet killing of subprocesses by SIGPIPE (as emerge has for  |
   |         | a long time). Thanks to Harald van Dijk truedfx@g.o for this |
   |         | patch.                                                       |

   | 15824   | Add references to bug #309001 in comments about SIGPIPE      |
   | zmedico | handling.                                                    |

   | 15825   | Bug #309001 - Install a SIGPIPE handler inside _exec for all |
   | zmedico | forked processes.                                            |

svn path=/main/branches/prefix/; revision=15836