Updated pkglint to 5.4.3.

Changes since 5.4.2:

* Variables like ${VAR_${OTHER_VAR}} are no longer checked for
  use/define mismatch
* The check for plural variable names has been removed
* The type of variables called *DESTDIR is no longer guessed to be a
  directory name
* The check for unknown shell commands is disabled in Makefile
  sections that depend on OPSYS
* The experimental hand-written shell parser has been replaced with
  a Yacc-generated one
* Meta packages don't need a LICENSE
* When PKGNAME is defined in terms of ${DISTNAME:S/from/to/:tl}, more
  modifiers (like :tl) are handled properly
* When the MAINTAINER or OWNER of a package is not the current user,
  a warning is printed for modified files
* The check for share/applications/*.desktop has been disabled, since
  pkglint would need to inspect the file's actual contents to see
  whether desktopdb.mk must be included or not
* SUBST_CLASSES may also be SUBST_CLASSES.NetBSD
* Loosened the usage restrictions for several variables, e.g. many
  variables that may be appended in a Makefile may also be set
  unconditionally
* PKG_OPTIONS_VAR must be of the form PKG_OPTIONS.*

(rillig)