produce a list of unique filenames:
"While attempting to build an RPM using distutils on Python 2.0,
rpm complained about duplicate files. The following patch fixed
that problem.
'convert_paths()' method to convert them all to the local syntax (backslash
or colon or whatever) at the appropriate time.
Added SCHEME_KEYS to get rid of one hard-coded list of attributes (in
'select_scheme()').
Default 'install_path_file' to true, and never set it false (it's just
there in case some outsider somewhere wants to disable installation of the
.pth file for whatever reason).
Toned down the warning emitted when 'install_path_file' is false, since we
no longer know why it might be false.
Added 'warn_dir' flag to suppress warning when installing to a directory
not in sys.path (again, we never set this false -- it's there for outsiders
to use, specifically the "bdist_*" commands).
Pulled the loop of 'change_root()' calls out to new method 'change_roots()'.
Comment updates/deletions/additions.
of globals from sysconfig.
Added 'prefix' and 'exec_prefix' to the list of variables that can be
expanded in installation directories (preserving the stupid old names
of 'sys_prefix' and 'sys_exec_prefix, though).
participates in the "--root" hack, ie. it also has a new root directory
hacked on at the very last minute (essential if the .pth file is to be
included in an RPM or other smart installer!).
the "install_data" command to the installation base, which is usually just
sys.prefix. (Any setup scripts out there that specify data files will have
to set the installation directory, relative to the base, explicitly.)
* Command method 'find_peer()' -> 'get_finalized_command()'
* Command method 'run_peer()' -> 'run_command()'
Also deleted the 'get_command_option()' method from Command, and
fixed the one place where it was used (in "bdist_dumb").
* 'headers' entry added to all the install schemes
* '--install-headers' option added
* 'install_headers' added to 'sub_commands'
* added 'dist_name' to configuration variables (along with a few
others that seem handy: 'dist_version', 'dist_fullname', and
'py_version'
* in 'finalize_unix()', make sure 'install_headers' defined if
user specified 'install_base' and/or 'install_platbase'
* added 'has_headers()'
* a few other small changes
