cURL 7.71.0

What's new in this version:

Changes:
- CURLOPT_SSL_OPTIONS: optional use of Windows' CA store (with openssl)
- Setopt: add CURLOPT_PROXY_ISSUERCERT(_BLOB) for coherency
- Setopt: support certificate options in memory with struct curl_blob
- Tool: Add option --retry-all-errors to retry on any error

Bugfixes:
- *_sspi: fix bad uses of CURLE_NOT_BUILT_IN
- All: fix codespell errors
- Altsvc: bump to h3-29
- Altsvc: fix 'dsthost' may be used uninitialized in this function
- Altsvc: fix parser for lines ending with CRLF
- Altsvc: remove the num field from the altsvc struct
- Appveyor: add non-debug plain autotools-based build
- Appveyor: disable flaky test 1501 and ignore broken 1056
- Appveyor: disable test 1139 instead of ignoring it
- Asyn-*: remove support for never-used NULL entry pointers
- Azure: use matrix strategy to avoid configuration redundancy
- Build: disable more code/data when built without proxy support
- Buildconf: remove -print from the find command that removes files
- Checksrc: enhance the ASTERISKSPACE and update code accordingly
- CI/macos: fix 'is already installed' errors by using bundle
- Cirrus: disable SFTP and SCP tests
- CMake: add ENABLE_ALT_SVC option
- CMake: add HTTP/3 support (ngtcp2+nghttp3, quiche)
- CMake: add libssh build support
- CMake: do not build test programs by default
- CMake: fix runtests.pl with CMake, add new test targets
- CMake: ignore INTERFACE_LIBRARY targets for pkg-config file
- CMake: rebuild Makefile.inc.cmake when Makefile.inc changes
- CODE_REVIEW.md: how to do code reviews in curl
- Configure: fix pthread check with static boringssl
- Configure: for wolfSSL, check for the DES func needed for NTLM
- Configure: only strip first -L from LDFLAGS
- Configure: repair the check if argv can be written to
- Configure: the wolfssh backend does not provide SCP
- Connect: improve happy eyeballs handling
- Connect: make happy eyeballs work for QUIC (again)
- Curl.1: Quote globbed URLs
- Curl: remove -J "informational" written on stdout
- Curl_addrinfo: use one malloc instead of three
- CURLINFO_ACTIVESOCKET.3: clarify the description
- Doc: add missing closing parenthesis in CURLINFO_SSL_VERIFYRESULT.3
- Doc: Rename VERSIONS to VERSIONS.md as it already has Markdown syntax
- Docs/HTTP3: add qlog to the quiche build instruction
- Docs/options-in-versions: which version added each cmdline option
- Docs: unify protocol lists
- Dynbuf: introduce internal generic dynamic buffer functions
- Easy: fix dangling pointer on easy_perform fail
- Examples/ephiperfifo: turn off interval when setting timerfd
- Examples/http2-down/upload: add error checks
- Examples: remove asiohiper.cpp
- FILEFORMAT: add more features that tests can depend on
- FILEFORMAT: describe verify/stderr
- Ftp: make domore_getsock() return the secondary socket properly
- Ftp: mark return-ignoring calls to Curl_GetFTPResponse with (void)
- Ftp: shut down the secondary connection properly when SSL is used
- GnuTLS: Backend support for CURLINFO_SSL_VERIFYRESULT
- Hostip: make Curl_printable_address not return anything
- Hostip: on macOS avoid DoH when given a numerical IP address
- Http2: keep trying to send pending frames after req.upload_done
- Http2: simplify and clean up trailer handling
- HTTP3.md: clarify cargo build directory
- Http: move header storage to Curl_easy from connectdata
- Libcurl.pc: Merge Libs.private into Libs for static-only builds
- Libssh2: improved error output for wrong quote syntax
- Libssh2: keep sftp errors as 'unsigned long'
- Libssh2: set the expected total size in SCP upload init
- Libtest/cmake: Remove commented code
- List-only.d: this option existed already in 4.0
- Manpage: add three missing environment variables
- Multi: add defensive check on data->multi->num_alive
- Multi: implement wait using winsock events
- Ngtcp2: cleanup memory when failing to connect
- Ngtcp2: fix build with current ngtcp2 master implementing draft 28
- Ngtcp2: fix happy eyeballs quic connect crash
- Ngtcp2: introduce qlog support
- Ngtcp2: never call fprintf() in lib code in release version
- Ngtcp2: update with recent API changes
- Ntlm: enable NTLM support with wolfSSL
- OpenSSL: have CURLOPT_CRLFILE imply CURLSSLOPT_NO_PARTIALCHAIN
- Openssl: set FLAG_TRUSTED_FIRST unconditionally
- Projects: Add crypt32.lib to dependencies for all OpenSSL configs
- Quiche: enable qlog output
- Quiche: update SSLKEYLOGFILE support
- Revert "buildconf: use find -execdir"
- Revert "ssh: ignore timeouts during disconnect"
- Runtests: remove sleep calls
- Runtests: show elapsed test time with higher precision (ms)
- Select: always use Sleep in Curl_wait_ms on Win32
- Select: fix overflow protection in Curl_socket_check
- Sendf: make failf() use the mvsnprintf() return code
- Server/sws: fix asan warning on use of uninitialized variable
- Server/util: fix logmsg format using curl_off_t argument
- Sha256: fixed potentially uninitialized variable
- Share: don not set the share flag it something fails
- Sockfilt: make select_ws stop waiting on exit signal event
- Socks: detect connection close during handshake
- Socks: fix expected length of SOCKS5 reply
- Socks: remove unreachable breaks in socks.c and mime.c
- Source cleanup: remove all custom typedef structs
- Test1167: fixes in badsymbols.pl
- Test1177: look for curl.h in source directory