branches: 1.11.6;

NFC: DEBUG only change - provide an externally visible (to the DEBUG sh
internals) interface to one of the internal (private to trace code) functions

branches: 1.10.2;

The beginnings of the great shell DEBUG (tracing) upgrade of 2017...

First, be aware that the DEBUG spoken of here has nothing whatever to
do with MKDEBUG=true type builds of NetBSD. The only way to get a
DEBUG shell is to build it yourself manually.

That said, for non-DEBUG shells, this change makes only one slight
(trivial really) difference, which should affect nothing.

Previously some code was defined like ...

function(args)
{
#ifdef DEBUG
/* function code goes here */
#endif
}

and called like ...

#ifdef DEBUG
function(params);
#endif

resulting in several empty functions that are never called being
defined in non-DEBUG shells. Those are now gone. If you can detect
the difference any way other than using "nm" or similar, I'd be very
surprised...

For DEBUG shells, this introduces a whole new TRACE() setup to use
to assist in debugging the shell.

I have had this locally (uncommitted) for over a year... it helps.

By itself this change is almost useless, nothing really changes, but
it provides the framework to allow other TRACE() calls to be updated
over time. This is why I had not committed this earlier, my previous
version required a flag day, with all the shell's internal tracing
being updated a once - which I had done, but that shell version has
bit-rotted so badly now it is almost useless...

Future updates will add the mechanism to allow the new stuff to actually
be used in a productive way, and following that, over time, gradual
conversion of all the shell tracing to the updated form (as required,
or when I am bored...)

The one useful change that we do get now is that the fd that the shell
uses for tracing (which was usually 3, but not any more) is now protected
from user/script interference, like all the other shell inernal fds.

There is no doc (nor will there be) on any of this, if you are not reading
the source code it is useless to you, if you are, you know how it works.

branches: 1.9.2;

Undo local changes not intended to be committed (and certainly not
with that commit message) in the previous update. This stuff works,
and will probably appear sometime, but not right now.

Have "make clean" remove sh.html1 and adapt it to clean trace files
the way they have been generated the past 20 years or so...

branches: 1.7.80; 1.7.84;
Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22249, verified by myself.

Support command -p, -v and -V as posix
Stop temporary PATH assigments messing up hash table
Fix sh -c -e "echo $0 $*" -a x (as posix)
(agreed by christos)

Fixes from David Laight:
- ansification
- format of output of jobs command (etc)
- job identiers %+, %- etc
- $? and $(...)
- correct quoting of output of set, export -p and readonly -p
- differentiation between nornal and 'posix special' builtins
- correct behaviour (posix) for errors on builtins and special builtins
- builtin printf and kill
- set -o debug (if compiled with DEBUG)
- cd src obj (as ksh - too useful to do without)
- unset -e name, remove non-readonly variable from export list.
(so I could unset -e PS1 before running the test shell...)

Sprinkle some `const's in DEBUG bracketed code.

branches: 1.3.6;
add forward declaration of union node;

PR/2808: Don't define DEBUG and #ifdef out functions not needed when DEBUG
is not defined (from FreeBSD).

branches: 1.1.6;
Merge in my changes from vangogh, and fix the x=`false`; echo $? == 0
bug.