Call fmtmsg/getdate/getdate_err useless.

They're POSIX, and they're implemented in iOS and glibc, but they're
not actually used in any codebase I have access to. They're *defined*
in several places, and some of those places have a handful of tests,
but I couldn't find a single genuine caller.

Bug: N/A
Test: N/A
Change-Id: Id3e2c36183fcff323aa5a2e3a3dabaa8378fae56