IN  PCHAR NewSystemPartition

Routine Description:

    This routine adds a system partition to the SystemPartition environment
    variable, and updates the Osloader, OsloadPartition, OsloadFilename,
    and OsloadOptions variables.


    SystemPartition - Supplies a pointer to the pathname of the system
                      partition to add.

Return Value:

    If the system partition was successfully added, ESUCCESS is returned,
    otherwise an error code is returned.

    BUGBUG - This program is simplistic and doesn't attempt to make sure all
    the variables are consistent.  It also doesn't fail gracefully.