t/lib/warnings/9uninit: Skip crypt tests if !d_crypt
t/op/taint.t: Skip crypt tests if !d_crypt
t/run/switches.t: Skip setlocale tests if !d_setlocale
t/op/magic.t: Comment for an unlink test
t/op/getpid.t: Silence undef warnings if getconf doesn't exist.

If a platform has getppid() but not getconf and we're building a
threaded perl, this file would've shown undef warnings, although
no tests were affected.
t/op/threads-dirh.t: Only test telldir and seekdir if they are available
ext/POSIX/t/time.t: Conditionalize the use of setlocale/LC_TIME

On Android, all locales are simply disabled, which broke the assumption
that LC_TIME is always available.