Auto merge of #1205 - alecmocatta:master, r=gnzlbg

Comment FIOSEEK* until they're in a NetBSD release

Accidentally included two constants that aren't in the current release of NetBSD.

While this doesn't impact libc-consumers, failing the testsuite on latest NetBSD isn't ideal.

I've commented them out; they can be reintroduced when the next NetBSD ships with them included.