To be addressed in 7.21.5
=========================

271 - fix the IPv6-working probing to only exist at one place in the code and
      only get done once

272 - re-using connections bound to local port

273 - Ben Noordhuis' imap + ssl patch

274 - Ben Noordhuis' smtp + ssl patch

275 - avoid sending USER?

276 - Karl M's vc makefile patch

277 - The "Stall when uploading to sftp using multi interface"  bug

278 - "Configure  $as_echo does not work"

279 - curl_multi_remove_handle() crashes

280 - Marcus Sundberg's gss patch

281 -