ROUTINE
-------

INT_ ug_backup_file (char File_Name[])

DESCRIPTION
-----------

Backup file. The backup file will have the save name as the existing file with
a suffix of ".bak".

INPUT ARGUMENTS
---------------

File_Name                : File name.

RETURN VALUE
---------------

0                        : No errors occurred backing up file.
<0                       : Errors occurred backing up file.
