cURL 7.73.0

What's new in this version:

Changed:
- curl: add --output-dir
- curl: support XDG_CONFIG_HOME to find .curlrc
- curl: update --help with categories
- curl_easy_option_*: new API for meta-data about easy options
- CURLE_PROXY: new error code
- mqtt: enable by default
- sftp: add new quote commands 'atime' and 'mtime'
- ssh: add the option CURLKHSTAT_FINE_REPLACE
- tls: add CURLOPT_SSL_EC_CURVES and --curves

Fixed:
- altsvc: clone setting in curl_easy_duphandle
- base64: also build for smtp, pop3 and imap
- BUGS: convert document to markdown
- build-wolfssl: fix build with Visual Studio 2019
- buildconf: invoke 'autoreconf -fi' instead
- checksrc: detect // comments on column 0
- checksrc: verify do-while and spaces between the braces
- checksrc: warn on space after exclamation mark
- CI/azure: disable test 571 in the msys2 builds
- CI/azure: MQTT is now enabled by default
- CI/azure: no longer ignore results of test 1013
- CI/tests: fix invocation of tests for CMake builds
- CI/travis: add a CI job with openssl3 (from git master)
- cleanups: avoid curl_ on local variables
- CMake: add option to enable Unicode on Windows
- cmake: make HTTP_ONLY also disable MQTT
- CMake: remove explicit `CMAKE_ANSI_CFLAGS`
- cmake: remove scary warning
- cmdline-opts/gen.pl: generate nicer "See Also" in curl.1
- configure: don't say HTTPS-proxy is enabled when disabled
- configure: fix pkg-config detecting wolfssl
- configure: let --enable-debug set -Wenum-conversion with gcc >= 10
- conn: check for connection being dead before reuse
- connect.c: remove superfluous 'else' in Curl_getconnectinfo
- curl.1: add see also no-progress-meter on two spots
- curl.1: fix typo invokved -> invoked
- curl: in retry output don't call all problems "transient"
- curl: make --libcurl show binary posts correctly
- curl: make checkpasswd use dynbuf
- curl: make file2memory use dynbuf
- curl: make file2string use dynbuf
- curl: make glob_match_url use dynbuf
- curl: make sure setopt CURLOPT_IPRESOLVE passes on a long
- curl: retry delays in parallel mode no longer sleeps blocking
- curl: use curlx_dynbuf for realloc when loading config files
- curl:parallel_transfers: make sure retry readds the transfer
- curl_get_line: build only if cookies or alt-svc are enabled
- curl_mime_headers.3: fix the example's use of curl_slist_append
- Curl_pgrsTime - return new time to avoid timeout integer overflow
- Curl_send: return error when pre_receive_plain can't malloc
- dist: add missing CMake Find modules to the distribution
- docs/LICENSE-MIXING: remove
- docs/opts: fix typos in two manual pages
- docs/RESOURCES: remove
- docs/TheArtOfHttpScripting: convert to markdown
- docs: add description about CI platforms to CONTRIBUTE.md
- docs: correct non-existing macros in man pages
- doh: add error message for DOH_DNS_NAME_TOO_LONG
- dynbuf: make sure Curl_dyn_tail() zero terminates
- easy_reset: clear retry counter
- easygetopt: pass a valid enum to avoid compiler warning
- etag: save and use the full received contents
- ftp: a 550 response to SIZE returns CURLE_REMOTE_FILE_NOT_FOUND
- ftp: avoid risk of reading uninitialized integers
- ftp: get rid of the PPSENDF macro
- ftp: make a 552 response return CURLE_REMOTE_DISK_FULL
- ftp: separate FTPS from FTP over "HTTPS proxy"
- git: ignore libtests in 3XXX area
- github: use new issue template feature
- HISTORY: mention alt-svc added in 2019
- HTTP/3: update to OpenSSL_1_1_1g-quic-draft-29
- http: consolidate nghttp2_session_mem_recv() call paths
- http_proxy: do not count proxy headers in the header bytecount
- http_proxy: do not crash with HTTPS_PROXY and NO_PROXY set
- imap: make imap_send use dynbuf for the send buffer management
- imap: set cselect_bits to CURL_CSELECT_IN initially
- ldap: reduce the amount of #ifdefs needed
- lib/Makefile.am: bump VERSIONINFO due to new functions
- lib1560: verify "redirect" to double-slash leading URL
- lib583: fix enum mixup
- lib: fix -Wassign-enum warnings
- lib: make Curl_gethostname accept a const pointer
- libssh2: handle the SSH protocols done over HTTPS proxy
- libssh2: pass on the error from ssh_force_knownhost_key_type
- Makefile.m32: add ability to override zstd libs [ci skip]
- man pages: switch to https://example.com URLs
- MANUAL: update examples to resolve without redirects
- mbedtls: add missing header when defining MBEDTLS_DEBUG
- memdebug: remove 9 year old unused debug function
- multi: expand pre-check for socket readiness
- multi: handle connection state winsock events
- multi: implement wait using winsock events
- ngtcp2: adapt to new NGTCP2_PROTO_VER_MAX define
- ngtcp2: adapt to the new pkt_info arguments
- ntlm: fix condition for curl_ntlm_core usage
- openssl: avoid error conditions when importing native CA
- openssl: consider ALERT_CERTIFICATE_EXPIRED a failed verification
- openssl: Fix wincrypt symbols conflict with BoringSSL
- parsedate: tune the date to epoch conversion
- pause: only trigger a reread if the unpause sticks
- pingpong: use a dynbuf for the *_pp_sendf() function
- READMEs: convert several to markdown
- runtests: add %repeat[]% for test files
- runtests: allow creating files without newlines
- runtests: allow generating a binary sequence from hex
- runtests: clear pid variables when failing to start a server
- runtests: make cleardir() erase dot files too
- runtests: provide curl's version string as %VERSION for tests
- schannel: fix memory leak when using get_cert_location
- schannel: return CURLE_PEER_FAILED_VERIFICATION for untrusted root
- scripts: improve the "get latest curl release tag" logic
- sectransp: make it build with --disable-proxy
- select.h: make socket validation macros test for INVALID_SOCKET
- select: align poll emulation to return all relevant events
- select: fix poll-based check not detecting connect failure
- select: reduce duplication of Curl_poll in Curl_socket_check
- select: simplify return code handling for poll and select
- setopt: if the buffer exists, refuse the new BUFFERSIZE
- setopt: return CURLE_BAD_FUNCTION_ARGUMENT on bad argument
- socketpair: allow CURL_DISABLE_SOCKETPAIR
- sockfilt: handle FD_CLOSE winsock event on write socket
- src: spell whitespace without whitespace
- SSLCERTS: fix English syntax
- strerror: honor Unicode API choice on Windows
- symbian: drop support
- telnet.c: depend on static requirement of WinSock version 2
- test1541: remove since it is a known bug
- test163[12]: require http to be built-in to run
- test434: test -K use in a single line without newline
- test971: show test mismatches "inline"
- tests/data: Fix some mismatched XML tags in test cases
- tests/FILEFORMAT: document nonewline support for <file>
- tests/FILEFORMAT: document type=shell for <command>
- tests/server/util.c: fix support for Windows Unicode builds
- tests: remove pipelining tests
- tls: fix SRP detection by using the proper #ifdefs
- tls: provide the CApath verbose log on its own line
- tool_setopt: escape binary data to hex, not octal
- tool_writeout: add new writeout variable, %{num_headers}
- travis: add a build using libressl (from git master)
- url: use blank credentials when using proxy w/o username and password
- urlapi: use more Curl_safefree
- vtls: deduplicate client certificates in ssl_config_data
- win32: drop support for WinSock version 1, require version 2
- winbuild: convert the instruction text to README.md