Log Message:
pkgtools/pkglint: update to 19.4.2

Changes since 19.4.1:

Fixed variable resolution. Before, variables that had not been defined
in an included file could still end up in the scope of the package,
which made many of the pkglint checks unreliable.

Each condition that is used in the PLIST should be defined somewhere in
the package Makefile or its included files.

When loading a package Makefile, hacks.mk is loaded implicitly at the
end, just as the pkgsrc infrastructure does in mk/bsd.hacks.mk.