This directory contains the kernel changes needed for process control.
They are ifdeffed as MENLO_JCL.  Note that the code in here is
NOT DEBUGGED and if you intend to install it you should be prepared
to do a good deal of debugging.  As I understand it, the system
crashes when this stuff is in.  Something about signals getting
sent to process zero.

Note that the files in this directory are taken from a kernel about
4 weeks older than the distributed kernel, so there may be fixes that
need to be installed to these files.  In other words, don't just copy
them into the sys directory.

A copy of the 4.1bsd csh is enclosed, since you'll need that to make
any use of these facilities.  Some other programs should be recompiled
after this is installed, notably ex, more, tset, Mail, and curses.
Probably some others too (snake?).  Most of these programs use ifdefs
on things like SIGTSTP rather than MENLO_JCL, so if you just install
the new signal.h and recompile without running process control,
bad things will probably happen.

As I understand it (thirdhand) the changes to make process control
work include:
	32 signals
	signal mechanism reworked drastically to make it more reliable.
	tty driver: ^Z sends SIGTSTP to all processes in pgrp, ^Y does
		too but not until it's read from tty.
	A stopped process is put into the "trace" state used by ptrace.
	A started process picks up where it left off.
	There are more signals, and more ioctls.
