FD passing on 64-bit is hosed
I first discovered this by running dovecot2 from pkgsrc, and got the
dovecot: imap-login: Error: fd_send(imap, 20) failed: Invalid argument
After some discussion on IRC, we came to the conclusion that something
isn't right with the CMSG macros on 64-bit systems.
Venkatesh Srinivas wrote a test program that I've attached to this email
that prints "hello" on 32-bit, and loops forever on 64-bit.