ROUTINE
-------

INT_ ug_read_arg_file (int *argc,
                         int *argc,
                         INT_ Message_Flag)

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

Read an input argument file (*.arg) and add the arguments read to the beginning
of the input argument vector.

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

argc              : Pointer to input argument count.
argv              : Pointer to pointer to input argument vector.
Message_Flag      : Message flag.
                    If Message_Flag >= 1 then progress information is written to
                    standard output.

OUTPUT ARGUMENTS
----------------

argc              : Pointer to new argument count.
argv              : Pointer to pointer to new argument vector (containing
                    entries in the argument file).

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

0                 : Arguments were read and added successfully.
>400              : An error occurred reading the input argument file or
                    re-allocating argument vector.
