Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Backout libinstall.a -> libpkg commit.

Discussed with: erwin, brooks, bapt

- Replace rather inefficient bubble sort with a recursive depth-first search.
This speeds up registration of packages considerably.
- style(9) police welcome!

PR: bin/112630
Submitted by: Stephen Montgomery-Smith <stephen@cauchy.math.missouri.edu>
Tested by: bento i386 experimental run
MFC after: 14 days

- pkg_info: flag -r: (show packages this packages depends on (documentation change))

- pkg_info: new flag -j (show the requirements script)

- pkg_info: fix verbose output when used on packages

- better handling of corrupt entries in /var/db/pkg

- differ between corrupt entires and packages not installed

- various small fixes

PR: 56989, 57016, 57029, 26468

- Make use of DEPOROGINs (if there are any) when installing package;
- fix few bogosities here and there;
- move some common routines into the library.

MFC after: 2 weeks

replace __FUNCTION__ with standardized __func__.

Requested by: jhb

New feature: allow origins of all dependencies be recorded into package list
using new `@comment DEPORIGIN:...' directive. This would allow us to make
many neat things including:

- easier binary upgrades;
- source upgrades without using external tools by simply extending
bsd.port.mk and pkg_install tools;
- mixed-mode upgrades (source + binary);
- depreciate and deorbit silly +REQUIRED_BY files in the near future.

This feature is no-op until appropriate bsd.port.mk patch is committed, and
even when it is already committed packages generated will remain 100%
compatible with old set of pkg_install tools (module all those neat
features, of course).

MFC after: 6 days

Fix SCM ID's.

Make sortdeps() working with dependency lists containing one or no elements.

Submitted by: roam
MFC in: 1 week

WARNS=2 cleanup.

Tested on: i386, alpha
MFC after: 2 weeks

Various fixes and improvements:
- fix harmless compiler's warnings (unused variables and missed prototype);
- before refusing to delete package because "there are packages installed
that require this package" check that packages in question is actually
installed;
- add new `-r' option to pkg_delete(8), which instructs it to delete not only
packages specified at command line, but all packages that depend on
specified packages as well.

MFC after: 2 weeks

Cosmetics: replace dozen instances of "(tmp = getenv(PKG_DBDIR) ? tmp : DEF_LOG_DIR)"
with macro.

MFC after: 1 month

- Add which(1)-like functionality into pkg_info;
- fix a harmless bug in match_installed() function introduced in my last
commit;
- uniformely reorder includes across files.

Submitted by: Garrett Rooney <rooneg@electricjellyfish.net>
Not objected by: jkh, -ports

When creating a package sort dependencies in such a way that if dependency
A depends on dependency B then dependency A will be in all cases listed
before B, so ``pkg_add -r'' will fetch/install packages in the correct order.

Previously dependencies were sorted just by its names, which is why
``pkg_add -r'' never actually worked properly.

To be usefull, hovewer, this fix requires that all packages have been
rebuilt, so it will take some time until users would be able to feel
posititive improvements. For the same reasons it is desirable to propagate
these changes to the 4-stable package building cluster *before* 4.3 ports
freeze, so packages for 4.3-RELEASE would be properly prepared.

Prompted by: kris
Insanely appreciated by: obrien
Silently approved by: jkh, -ports