Merged from trunk -r15780:15790

   Merged from trunk -r15780:15790

   | 15783   | Bug #303567 - Create implicit dependencies on libc, in order |
   | zmedico | to ensure that libc is installed as early as possible.       |

   | 15784   | Fix typo in parenthesis from previous commit.                |
   | zmedico |                                                              |

   | 15787   | Add support for displaying profile listed in                 |
   | zmedico | make.profile/parent when make.profile is not a symlink. The  |
   |         | first parent with a path inside $PORTDIR is displayed.       |

   | 15789   | If _implicit_libc_deps() finds both a new-style virtual and  |
   | zmedico | an old-style PROVIDE virtual, use the new-style virtual.     |

   | 15790   | Add --debug output for the scheduler digraph.                |
   | zmedico |                                                              |

svn path=/main/branches/prefix/; revision=15799