Log Message:
pkgtools/pkglint: update to 21.2.1

Changes since 21.2.0:

Files whose names ends in '~' are ignored by pkglint since they are
ignored by CVS as well.

Variables with name BUILDLINK_TRANSFORM.* may contain '-Wl,-rpath,'
directly in commands of the form 'rm:*', just like their counterpart
BUILDLINK_TRANSFORM without a package name in the variable name.

Several new tests.