branches: 1.15.20;
No space in "function()", "command;" or "$(command)".
Requested by christos.

Oops, missed a few echo >&2 changes in previous commit.

Detect cyclic dependencies, and abort if any exist.

Approved by christos

Document input and output format for syspkgdeps and culldeps.

Approved by christos

When printing messages to stderr, always use
echo >&2 "${prog}: ..."

Approved by christos

* Add a special case for sets="all".
* Use dirname, don't try to use a shortcut that doesn't always work.
This uses the cheap implementation of dirname from sets.subr.
* Fix error in getopts string ("-p" option takes an arg).
* Explicitly use ${HOST_SH} to run culldeps script, because we might
be on a host where /bin/sh is not a POSIX shell.

Reviewed by agc

Ensure that (almost) all shell variables in distrib/sets/* scripts are
used with curly braces and quotes, as in "${var}".

Also ensure that command substitution is quoted, as in "$(command)", and
convert `command` to $(command).

Reviewed by agc

Add shell variables defined in sets.subr for almost all commands used
by scripts in distrib/sets/*. This is intended to be useful when cross
building. Only trivial commands like echo, cat, and rm are excluded
from this treatment.

While I am here, make ${MTREE} and ${DB} follow the pattern used by most
other such variables.

Reviewed by agc.

Move default values for several shell variables into sets.subr.

Reviewed by agc

Set default vars so blank and unset both end up w. a reasonable default

Make all the sets scripts work even when not run from the directory that
they reside in.
Change any uses of dirname to use shell variable substitution instead.

rename all the <bsd.own.mk> derived variables to uppercase, and export
them to the environment.

Significant overhaul of how the sets are used:

* Add an optional third field to the sets file which is a list of
comma separated keywords that control if the line is printed.
Currently supported keywords
kerberos4 ${MKKERBEROS4} != no
kerberos ${MKKERBEROS} != no
lint ${MKLINT} != no
obsolete ${obsolete} != 0.
In this case, non obsolete files are not printed.
(This will allow future support for builds with variables such as
MKHESIOD and MKYP set to "no".)

* Use sh(1)'s getopts where appropriate, and otherwise cleanup the
various scripts.

* Move defaults for sets.subr from sets.defaults into sets.subr.
Move replicated code for determining stuff such as shlibs type
from various scripts into sets.subr.

* Merge the obsolete.*, krb.*, krb4.* and lint.* into the appropriate
main lists with the relevant third field keyword(s).

Factor duplicated code for setting variables such as machine_cpu
and machine_arch to their defaults into sets.defaults, and source
it at the top of each script.

Also, to be consistent with variable naming, s/arch/machine_arch/.

sets.defaults introduces two new variables, krb and krb4, which
will affect whether Kerberos- or Kerberos IV-only files are put
into the set lists.

For System Packages, two new utilities, a subroutine library, and
a new list:

sets.subr -- The set-listing code that is common to makeplist,
makeflist, and regpkg has moved here.

syspkgdeps -- Compute naive dependencies for system packages based
on directory containment. I.e., if package A contains
path /p/q, and package B contains path /p, then B is
considered a dependency of A. As Jim Wise remarks,
this is not quite right: system-package dependencies
should indicate a functional dependency. Nevertheless,
these naive dependencies protect us from orphaning
files when pkg_delete'ing system packages.

culldeps -- Helper for syspkgdeps. Removes redundant dependencies
from a dependencies table. Essentially does the opposite
of a transitive closure on a dependencies table: if
the table contains A depends-on B, B depends-on C, and
A depends-on C, then A depends-on C is removed because
it can be derived from the prior two dependencies.

deps -- Dependencies computed by syspkgdeps.