Log message:
Modify the pkginstall framework so that it manages all aspects of
INSTALL/DEINSTALL script creation within pkgsrc.

If an INSTALL or DEINSTALL script is found in the package directory,
it is automatically used as a template for the pkginstall-generated
scripts.  If instead, they should be used simply as the full scripts,
then the package Makefile should set INSTALL_SRC or DEINSTALL_SRC
explicitly, e.g.:

	INSTALL_SRC=	${PKGDIR}/INSTALL
	DEINSTALL_SRC=	# emtpy

As part of the restructuring of the pkginstall framework internals,
we now *always* generate temporary INSTALL or DEINSTALL scripts.  By
comparing these temporary scripts with minimal INSTALL/DEINSTALL
scripts formed from only the base templates, we determine whether or
not the INSTALL/DEINSTALL scripts are actually needed by the package
(see the generate-install-scripts target in bsd.pkginstall.mk).

In addition, more variables in the framework have been made private.
The *_EXTRA_TMPL variables have been renamed to *_TEMPLATE, which are
more sensible names given the very few exported variables in this
framework.  The only public variables relating to the templates are:

	INSTALL_SRC		INSTALL_TEMPLATE
	DEINSTALL_SRC		DEINSTALL_TEMPLATE
				HEADER_TEMPLATE

The packages in pkgsrc have been modified to reflect the changes in
the pkginstall framework.

Log message:
Remove USE_PKGINSTALL from pkgsrc now that mk/install/pkginstall.mk
automatically detects whether we want the pkginstall machinery to be
used by the package Makefile.

Log message:
Use REQD_DIRS instead of MAKE_DIRS for directories under ${PREFIX} so
that these directories will be conditionally removed (based on reference
counts), regardless of the value of PKG_CONFIG.  Bump the PKGREVISION
for packages that were modified as a result.

Log message:
SUBST_FILES.* must be relative to ${WRKSRC}.

Log message:
Remove USE_BUILDLINK3 and NO_BUILDLINK; these are no longer used.

Log message:
Update to 1.3: show a more descriptive usage message, useful as a quick
reference.  Per tv@'s suggestion.

Log message:
Update to 1.2:
- Add support to explicitly select which wrappers are wanted on a system and
  which ones are not.  This is done through a configuration file that defines
  a filter with a set of actions and regular expressions (example file
  included).
- Add an examples section to the manual page with solutions for some FAQs.

Log message:
Fix Dt, and improve formatting.

Log message:
Explicitly use -g instead of relying on default behavior.

Log message:
Add the -g flag to explicitly select the "group mode" (previously known as
"package mode").  Use previous version bump for this change.