pkgconf: upgrade 1.9.4 -> 1.9.5

Changes from 1.9.4 to 1.9.5:
----------------------------

* 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.

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit fb9e0559)
Signed-off-by: Steve Sakoman <steve@sakoman.com>