These filters encode binary files as printable ascii files that should pass
through mail.  They also calculate and check end to end checksums.

btoa	"binary to ascii"
atob	"ascii to binary" (checks checksums, no output if bad)

"tarmail" and "untarmail" are shell scripts which make it convenient to tar
up directory structures, mail them to remote sites, and untar them.  The use
of tar ensures that protection modes, file dates, and (if su) owners are
recreated at the other end.  Using tarmail has been more convienent (in our
situation) than using uucp directly.

The "btoa" encoding is slightly more efficient than uuencode (especially if
the data has zero padding, as many object file formats do).  I find btoa/atob
easier to use than uuencode/uudecode because they are straight filters
(uuencode wants to create the file and mode for you).  Also, it is nice to
have the additional assurance of the checksums, to protect against mistakes,
wild mailers, and the general unknown.

IF you are on a 16-bit machine, you will have to run around changing "int" to
"long" before these filters work.  If the c style looks a bit strange, that
is because the programs were written using a strange preprocessor.