This is version 3.1 of the editor. It is too large to fit on a pdp-11
unless you have overlay code. (Such code is expected to be available
for v7 unix soon.)

Version 2.9 corresponds to version 3.1 without the enhancements in 3.1.
There is no reason to use 2.9 unless you have a pdp-11 that does not have
overlay software, since 3.1 contains all the bug fixes and some new features.

Special installation notes for this version.
1) If on a V6 system using -lretro, be sure to remove the line in
   /usr/include/retrofit/sgtty.h that defines CBREAK. If you have
   added a line defining TIOCSETN or TIOCGETC these should be removed.
2) The include file varargs.h should be installed, as the new printf needs it.
3) The include file local/uparm.h should be installed, as ex_tune.h needs it.
   The contents of this include file can be modified if you wish to place
   the editor in a nonstandard location.
4) Be sure not to use the -t1 compiler (which puts switches in I space and
   hence makes larger I segments. This will causes the editor not to fit
   in 64K on an 11.
5) Use the -t0 compiler which has a large enough symbol table. (V6 only)
6) Be sure to use the new termlib that goes with this version of the editor.
7) Be sure to use the new termcap.
8) Make sure the programs setenv and printenv are installed, and that setenv
   is able to write /etc/htmp. (V6 only)

Conditional compilation flags:
	-DTRACE		for debugging (wont then fit on an 11)
	-DV6		for version 6, using raw (v7 uses cbreak)
	-DVFORK		for UCB Vax/Unix with the vfork system call.
	-DCHDIR		compile in undocumented old chdir (cd) command
	-DLISP		compile in lisp hacks
	-DUCVISUAL	compile in code to handle \ escapes for visual on
			upper case only terminals.  gross.

Ex means to avoid stdio like the plague. If any of stdio other than the
ctype.h functions or str* get pulled in, it is a mistake.

Ex is very large, but should fit (barely) on an 11/70.  There are only
a few bytes of room left in version 2.9 unless you take out some of
CHDIR, LISP, or UCVISUAL. This assumes the new termlib (which knows
about the tc= capability, 1024 byte entries, and @ cancellation of
capabilities); and that -t1 is NOT used for compilation.