Incompatibilities with scsh 0.4.4:

everything is defined at the top level, no modules.

generic-receive-message! always returns 2 values: the number of
bytes read and the address received from.  Likewise for receive-message!
and receive-message (bug in scsh?)

network-info works when its argument is a socket address (bug in scsh?)

%read-delimited! takes a string for its "set of delimiters" parameter.
If the buffer fills, it doesn't peek ahead to check whether the next
character is a delimiter or EOF, since this a) seems to require extra
code or comparisons, b) makes read-delimted! and read-line! more complex
c) doesn't gain much anyway.

set-enabled-interrupts and with-interrupts have not been 
implemented.  Within a with-enabled-interrupts form, all interrupts are
disabled.

set-command-line-args! is not implemented.
command-line returns the same list every time, not a copy.

itimer is not implemented.

Several scsh procedures are incompatible with Guile procedures.
In these cases the procedures are redefined when init.scm is
loaded.  This isn't a very good solution: hopefully use of the
module system will help.  The following procedures are
affected: read-delimited read-delimited! pipe sleep exit make-fluid
and probably open-file.

The close-on-exec flag is not currently set on unrevealed ports.

the NDBM interface hasn't been implemented.

the flock interface hasn't been implemented.

net-to-host-32 etc., haven't been defined.

the files jcontrol.scm and jcontrol2.scm haven't been ported.

pty and tty support hasn't been implemented (pty.scm, tty.scm).

select! hasn't been implemented.

display and write don't accept file descriptors in place of ports.
