MFC r281959,282885 (fanf, partial),282888 (fanf):

Try alternate addresses more agressively.

PR: 158125
Submitted by: Mark Andrews <marka isc org> (with changes from me)

whois: code cleanup

Use pedantically correct types.

whois: do not clobber command-line flags when tweaking O_NONBLOCK

This can make whois fail to follow referrals when it should.
The bug was introduced in r281959.