Make UDP sockets non-blocking. I've confirmed that at least on Linux 2.4 a
  read event can come back from poll() on a valid SOCK_DGRAM socket but
  recv(2) will still block. This patch doesn't ignore EAGAIN in
  read_udp_packets(), though maybe it should. (This patch was edited by Daniel
  Stenberg and a new configure test was added (imported from curl's configure)
  to properly detect what non-blocking socket approach to use.)

  I'm not quite sure how this was happening, but I've been seeing PTR queries
  which seem to return empty responses. At least, they were empty when calling
  ares_expand_name() on the record. Here's a patch which guarantees to
  NUL-terminate the expanded name. The old behavior failed to NUL-terminate if
  len was 0, and this was causing strlen() to run past the end of the buffer
  after calling ares_expand_name() and getting ARES_SUCCESS as the return
  value. If q is not greater than *s then it's equal and *s is always
  allocated with at least one byte.

- inspired by Tupone Alfredo's bug report (and patch) #1212940

address was not possible to use. It is now, but requires it written
RFC2732-style, within brackets - which incidently is how you enter numerical
IPv6 addresses in URLs. Test case 263 added to verify.

binary zeroes within the headers. They confused libcurl to do wrong so the
downloaded headers become incomplete. The fix is now verified with test case
262.

pkg-config

talking to sockfilt

can't be opened

to the docs.

"http://somehost?data" as it added a slash too much in the request ("GET
/?data/"...). Added test case 260 to verify.