duo_unix: compile with pam modules, and place in /usr/local/lib/pam/

Closes #34823.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
duo_unix: update 1.9.13_1 bottle.
duo_unix: general cleanup.
pure 0.64

Closes #34648.
depends_on :macos => :mavericks
pure: update 0.64 bottle.