Curl and libcurl 7.56.0

 Public curl releases:         169
 Command line options:         211
 curl_easy_setopt() options:   248
 Public functions in libcurl:  61
 Contributors:                 1600

This release includes the following changes:

 o curl: enable compression for SCP/SFTP with --compressed-ssh  [11]
 o libcurl: enable compression for SCP/SFTP with CURLOPT_SSH_COMPRESSION [11]
 o vtls: added dynamic changing SSL backend with curl_global_sslset() [28]

This release includes the following bugfixes:

 o examples/ftpuploadresume.c: use portable code
 o runtests: match keywords case insensitively
 o travis: build the examples too [1]
 o strtoofft: reduce integer overflow risks globally [2]
 o zsh.pl: produce a working completion script again [3]
 o cmake: remove dead code for CURL_DISABLE_RTMP [4]
 o progress: Track total times following redirects [5]
 o configure: fix --disable-threaded-resolver [6]
 o cmake: remove dead code for DISABLED_THREADSAFE [7]
 o configure: fix clang version detection
 o darwinssi: fix error: variable length array used
 o travis: add metalink to some osx builds [8]
 o configure: check for __builtin_available() availability [9]
 o http_proxy: fix build error for CURL_DOES_CONVERSIONS [10]
 o examples/ftpuploadresume: checksrc compliance
 o ftp: fix CWD when doing multicwd then nocwd on same connection [12]
 o system.h: remove all CURL_SIZEOF_* defines [13]
 o http: Don't wait on CONNECT when there is no proxy [14]
 o system.h: check for __ppc__ as well [15]
 o http2_recv: return error better on fatal h2 errors [16]
 o scripts/contri*sh: use "git log --use-mailmap"
 o tftp: fix memory leak on too long filename [17]
 o system.h: fix build for hppa [18]
 o cmake: enable picky compiler options with clang and gcc [19]
 o makefile.m32: add support for libidn2 [20]
 o curl: turn off MinGW CRT's globbing [21]
 o request-target.d: mention added in 7.55.0
 o curl: shorten and clean up CA cert verification error message [22]
 o imap: support PREAUTH [23]
 o CURLOPT_USERPWD.3: see also CURLOPT_PROXYUSERPWD
 o examples/threaded-ssl: mention that this is for openssl before 1.1
 o winbuild: fix embedded manifest option [24]
 o tests: Make sure libtests & unittests call curl_global_cleanup()
 o system.h: include sys/poll.h for AIX [25]
 o darwinssl: handle long strings in TLS certs [26]
 o strtooff: fix build for systems with long long but no strtoll [27]
 o asyn-thread: Improved cleanup after OOM situations
 o HELP-US.md: "How to get started helping out in the curl project" [29]

This release includes the following known bugs:

 o see docs/KNOWN_BUGS (https://curl.haxx.se/docs/knownbugs.html)

This release would not have looked like this without help, code, reports and
advice from friends like these:

  Benbuck Nason, Benjamin Sergeant, Bill Pyne, Brian Carpenter, Dan Fandrich,
  Daniel Stenberg, Even Rouault, Frank Denis, Gergely Nagy, Gisle Vanem,
  Jakub Zakrzewski, Jan Alexander Steffens, Johannes Schindelin,
  John David Anglin, joshhe on github, Kamil Dudka, Maksim Stsepanenka,
  Marcel Raad, Max Dymond, Michael Smith, Nick Zitzmann, Peter Lamare,
  Ray Satiro, Ryan Schmidt, Ryan Winograd, Tatsuhiro Tsujikawa, Viktor Szakáts,
  Nicolas Morey-Chaisemartin,
  (27 contributors)

        Thanks! (and sorry if I forgot to mention someone)

References to bug reports and discussions on issues:

 [1] = https://curl.haxx.se/bug/?i=1777
 [2] = https://curl.haxx.se/bug/?i=1758
 [3] = https://curl.haxx.se/bug/?i=1779
 [4] = https://curl.haxx.se/bug/?i=1785
 [5] = https://curl.haxx.se/bug/?i=1602
 [6] = https://curl.haxx.se/bug/?i=1784
 [7] = https://curl.haxx.se/bug/?i=1786
 [8] = https://curl.haxx.se/bug/?i=1790
 [9] = https://curl.haxx.se/bug/?i=1788
 [10] = https://curl.haxx.se/bug/?i=1793
 [11] = https://curl.haxx.se/bug/?i=1735
 [12] = https://curl.haxx.se/bug/?i=1782
 [13] = https://curl.haxx.se/bug/?i=1767
 [14] = https://curl.haxx.se/bug/?i=1803
 [15] = https://curl.haxx.se/bug/?i=1797
 [16] = https://curl.haxx.se/bug/?i=1021
 [17] = https://curl.haxx.se/bug/?i=1808
 [18] = https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=872502#10
 [19] = https://curl.haxx.se/bug/?i=1799
 [20] = https://curl.haxx.se/bug/?i=1815
 [21] = https://curl.haxx.se/bug/?i=1751
 [22] = https://curl.haxx.se/bug/?i=1810
 [23] = https://curl.haxx.se/bug/?i=1818
 [24] = https://curl.haxx.se/bug/?i=1832
 [25] = https://curl.haxx.se/bug/?i=1828
 [26] = https://curl.haxx.se/bug/?i=1823
 [27] = https://curl.haxx.se/bug/?i=1829
 [28] = https://curl.haxx.se/libcurl/c/curl_global_sslset.html
 [29] = https://curl.haxx.se/bug/?i=1837