more involved, but should hopefully not generate any compiler warnings on
win32 systems (that can't check the socket based on the numeric).

Windows (unrelated to select). select() can never set errno
to EINTR on Windows.

http://www.greenhills.co.uk/mak/gentoo/curl-eintr-bug.c, I now made the
select() and poll() calls properly loop if they return -1 and errno is
EINTR. glibc docs for this is found here:
http://www.gnu.org/software/libc/manual/html_node/Interrupted-Primitives.html

This last link says BSD doesn't have this "effect". Will there be a problem
if we do this unconditionally?
S: ----------------------------------------------------------------------

build out-of-the-box on BeOS.

Winsock sockets are not in range 0..FD_SETSIZE.
Shouldn't Curl_select() use curl_socket_t ?