Merged from trunk -r11446:11448

   Merged from trunk -r11446:11448

|11447  |Optimize LinkageMap to use tuples of device and inode numbers from stat calls, instead of paths from |
|zmedico|realpath, as unique keys for identification of files. This is the same approach used by              |
|       |dblink.isowner() for cases in which path comparison fails due to symlinks. Thanks to Lucian Poston   |
|       |<lucianposton@gmail.com> for submitting this patch (along with the missing-rebuild package set which |
|       |I haven't merged yet). These patches are hosted in the following location:                           |
|       |http://repo.or.cz/w/revdep-rebuild-reimplementation.git?a=tree;h=refs/heads/rc3;hb=refs/heads/rc3    |

|11448  |Update comment, from Lucian Poston's git repo.                                                       |
|zmedico|                                                                                                     |
   Merged from trunk -r11454:11455

   | 11455   | More LinkageMap enhancments from Lucian Poston: * Added      |
   | zmedico | _ObjectKey helper class to LinkageMap. (commit               |
   |         | eac5528887656abec65fc3a825506187397482e4) * Minor change to  |
   |         | docstrings. (commit                                          |
   |         | adde422145d81f25b4024eac1e78b80e1b4a4531)                    |

   Ported above commits to the LinkageMapMachO

svn path=/main/branches/prefix/; revision=11464