Why doesn't src/backend/port/win32/socket.c implement bind()?

Some of the Windows buildfarm members occasionally fail like this:

LOG:  could not bind IPv4 socket: No error
HINT:  Is another postmaster already running on port 64470? If not, wait a few seconds and retry.
WARNING:  could not create listen socket for "127.0.0.1"
FATAL:  could not create any TCP/IP sockets

(bowerbird, in particular, has a few recent examples)

I think the reason why we're getting "No error" instead of a useful
strerror report is that socket.c doesn't provide an implementation
of bind() that includes TranslateSocketError().  Why is that?
        regards, tom lane