cURL 7.72.0

What's new in this version:

Changes:
- content_encoding: add zstd decoding support
- CURL_PUSH_ERROROUT: allow the push callback to fail the parent stream
- CURLINFO_EFFECTIVE_METHOD: added

Bug-fixes:
- CVE-2020-8231: libcurl: wrong connect-only connection
- appveyor: collect libcurl.dll variants with prefix or suffix
- asyn-ares: correct some bad comments
- bearssl: fix build with disabled proxy support
- buildconf: avoid array concatenation in die()
- buildconf: retire ares buildconf invocation
- checksrc: ban gmtime/localtime
- checksrc: invoke script with -D to find .checksrc proper
- CI/azure: install libssh2 for use with msys2-based builds
- CI/azure: unconditionally enable warnings-as-errors with autotools
- CI/macos: enable warnings as errors for CMake builds
- CI/macos: set minimum macOS version
- CI/macos: unconditionally enable warnings-as-errors with autotools
- CI: Add muse CI analyzer
- cirrus-ci: upgrade 11-STABLE to 11.4
- CMake: don't complain about missing nroff
- CMake: fix test for warning suppressions
- cmake: fix windows xp build
- configure.ac: Sort features name in summary
- configure: allow disabling warnings
- configure: cleanup wolfssl + pkg-config conflicts when cross compiling.
- configure: show zstd "no" in summary when built without it
- connect: remove redundant message about connect failure
- curl-config: ignore REQUIRE_LIB_DEPS in --libs output
- curl.1: add a few missing valid exit codes
- curl: add %{method} to the -w variables
- curl: improve the existing file check with -J
- curl_multi_setopt: fix compiler warning "result is always false"
- curl_version_info.3: CURL_VERSION_KERBEROS4 is deprecated
- CURLINFO_CERTINFO.3: fix typo
- CURLOPT_NOBODY.3: clarify what setting to 0 means
- docs: add date of 7.20 to CURLM_CALL_MULTI_PERFORM mentions
- docs: Add video link to docs/CONTRIBUTE.md
- docs: change "web site" to "website"
- docs: clarify MAX_SEND/RECV_SPEED functionality
- docs: Update a few leftover mentions of DarwinSSL
- doh: remove redundant cast
- file2memory: use a define instead of -1 unsigned value
- ftp: don't do ssl_shutdown instead of ssl_close
- ftpserver: don't verify SMTP MAIL FROM names
- getinfo: reset retry-after value in initinfo
- gnutls: repair the build with `CURL_DISABLE_PROXY`
- gtls: survive not being able to get name/issuer
- h2: repair trailer handling
- http2: close the http2 connection when no more requests may be sent
- http2: fix nghttp2_strerror -> nghttp2_http2_strerror in debug messages
- libssh2: s/ssherr/sftperr/
- libtest/Makefile.am: add -no-undefined for libstubgss for Cygwin
- md(4|5): don't use deprecated macOS functions
- mprintf: Fix dollar string handling
- mprintf: Fix stack overflows
- multi: Condition 'extrawait' is always true
- multi: Remove 10-year old out-commented code
- multi: remove two checks always true
- multi: update comment to say easyp list is linear
- multi_remove_handle: close unused connect-only connections
- ngtcp2: adapt to error code rename
- ngtcp2: adjust to recent sockaddr updates
- ngtcp2: update to modified qlog callback prototype
- nss: fix build with disabled proxy support
- ntlm: free target_info before (re-)malloc
- openssl: fix build with LibreSSL < 2.9.1
- page-header: provide protocol details in the curl.1 man page
- quiche: handle calling disconnect twice
- runtests.pl: treat LibreSSL and BoringSSL as OpenSSL
- runtests: move the gnutls-serv tests to a dynamic port
- runtests: move the smbserver to use a dynamic port number
- runtests: move the TELNET server to a dynamic port
- runtests: run the DICT server on a random port number
- runtests: run the http2 tests on a random port number
- runtests: support dynamicly base64 encoded sections in tests
- setopt: unset NOBODY switches to GET if still HEAD
- smtp_parse_address: handle blank input string properly
- socks: use size_t for size variable
- strdup: remove the odd strlen check
- test1119: verify stdout in the test
- test1139: make it display the difference on test failures
- test1140: compare stdout
- test1908: treat file as text
- tests/FILEFORMAT.md: mention %HTTP2PORT
- tests/sshserver.pl: fix compatibility with OpenSSH for Windows
- TLS naming: fix more Winssl and Darwinssl leftovers
- tls-max.d: this option is only for TLS-using connections
- tlsv1.3.d. only for TLS-using connections
- tool_doswin: Simplify Windows version detection
- tool_getparam: make --krb option work again
- TrackMemory tests: ignore realloc and free in getenv.c
- transfer: fix data_pending for builds with both h2 and h3 enabled
- transfer: fix memory-leak with CURLOPT_CURLU in a duped handle
- transfer: move retrycount from connect struct to easy handle
- travis/script.sh: fix use of `-n' with unquoted envvar
- travis: add ppc64le and s390x builds
- travis: update quiche builds for new boringssl layout
- url: fix CURLU and location following
- url: silence MSVC warning
- util: silence conversion warnings
- win32: Add Curl_verify_windows_version() to curlx
- WIN32: stop forcing narrow-character API
- windows: add unicode to feature list
- windows: disable Unix Sockets for old mingw