Pkgconf

----------------------------

* Fix incorrect assumptions involving the use of ctype(3) functions.
Patch by Taylor R Campbell.

* Fix detection of provided functions on autoconf.
Patches by Harmen Stoppels.

* Fix deletion of tests/meson.build by the autoconf build system.
Patch by h30032433.

* Fix quoting rules in argvsplit.c.
Patch by huyubiao.

* Update libpkgconf documentation and documentation building scripts.
Patches by Andrew Shadura.

* Enforce maximum package count correctly for --modversion.

----------------------------

* Fix a buffer overflow vulnerability involving very large variable expansions.
CVE-2023-24056

* Fix a bunch of minor regressions with the solver.

* Create separate solutions for `--cflags` and `--libs` when `--static` is not
used.

* Remove final trailing whitespace in pkgconf_fragment_render_buf().

* Revert broken pkg.m4 change involving querying module versions in
PKG_CHECK_MODULES.

* Fix handling of tildes in version strings.

* Various C99 formatting string fixes involving SIZE_FMT_SPECIFIER.

----------------------------

* Fix a bunch of minor code issues pointed out using Clang static analyzer.

* New API: pkgconf_solution_free(), which frees a compiled solution graph.

* Fix behavior when overriding global variables with `--define-variable`.

----------------------------

* Do not try to break dependency cycles across dependency lists. This causes
the solved graph to sometimes miss required dependency nodes because the
solver detected an incorrect dependency cycle.

* New API: pkgconf_queue_solve(), which replaces pkgconf_queue_apply().
pkgconf_queue_apply is now deprecated and should not be used in new code.

----------------------------

* Skip graph flattening and traversal for query types which only make sense
for a single pkg-config module.

The old solver walked these graphs with --maximum-traverse-depth=1 in
these cases, but this is no longer helpful because the graph is flattened
by the new solver.

series. While it is believed to be suitable for production, there may be
bugs due to the overall redesign of the solver and other initiatives.
Additionally, a future release of pkgconf plans will have additional ABI
breaks for the libpkgconf library before the pkgconf 2.0 release is cut.

* There is now a new solver that is designed to provide higher performance
with complicated graphs, which works by flattening the dependency graph
into a smaller set of dependencies. This graph can then be evaluated
instead of the original dependency graph without having to visit every
edge in the graph.

NOTE: This solver, while providing significant performance improvements,
does so, at the cost of changed behavior for some edge cases (such as
circular dependencies).

* Bug fixes:
- Resolved several memory leaks with edge cases when using libpkgconf
directly.
- pkgconf CLI now consistently frees libpkgconf resources under all
circumstances.
- SYSROOT rules are no longer applied to `-uninstalled` packages by
default. Use `PKG_CONFIG_PKGCONF1_SYSROOT_RULES` for legacy behavior.

* A new `--license` selector has been added to the pkgconf CLI. This uses
SPDX expressions which can be set as the `License` field in `.pc` files.
See the `pc(5)` manpage for more information.

* The canonical location for pkgconf maintenance going forward is
<https://gitea.treehouse.systems/ariadne/pkgconf>. This is presently
mirrored to GitHub for user convenience, but that mirroring will
be terminated at some point (due to GitHub Copilot).