Log Message:
pkgtools/pkglint: update to 20.1.10

Changes since 20.1.8:

Recognize SUBST_NOOP_OK and SUBST_SHOW_DIFF.

Allow plain -Wl,-R and -Wl,-rpath in BUILDLINK_TRANSFORM, when they are
used to remove compiler options.

Recognize ggrep and other platform tools as valid tool names.  Seen in
lang/rust.