curl and libcurl 8.21.1

 Public curl releases:         276
 Command line options:         274
 curl_easy_setopt() options:   308
 Public functions in libcurl:  100
 Authors:                      1490
 Contributors:                 3734

This release includes the following changes:


This release includes the following bugfixes:

 o autotools: minor fixes and improvements [33]
 o build: enable thread-safe `getaddrinfo()` for OpenBSD, and other tidy-ups [35]
 o cmake: dedupe expressions into local vars in `cmake_uninstall.in.cmake` [9]
 o cmake: fix not to build `tunits` when `BUILD_CURL_EXE=OFF` [7]
 o cmake: flatten build tree, tidy up base dir variables [12]
 o cmake: replace deprecated `remove` command with `rm` and pass arg safely [11]
 o cmake: robustify base path in local file reference [15]
 o cmake: stop probing unused `float.h` for `STDC_HEADERS` [10]
 o conncache: connection alive checks intervals [20]
 o curl-functions.m4: verify working RFC 4291 zero prefixed IPv4 - mapped format [41]
 o gopher: reject CR and LF in the selector [1]
 o http: trim custom header name before the Authorization drop [17]
 o INSTALL.md: add building-from-source overview section [29]
 o ldap: support insecure mode for Windows native LDAP [3]
 o lib1587: fix gcc `-Wconversion` with LibreSSL on Windows, test in CI [6]
 o mqtt: reject control bytes in the topic [43]
 o multi: forbid curl_easy_pause from within multi socket callback [22]
 o openssl: drop unused pre-OpenSSL3 `ctx_option_t` typedef [8]
 o runtests: restore `-k` option and actively process as no-op [32]
 o scripts: use end-of-options marker in `cd`, `mkdir`, `mv`, `sha256sum` commands [34]
 o sws: allow connection-monitor to log all disconnects [2]
 o test 1560: test RFC4291 style IPv6 IPv4-mapped addresses [40]
 o tool: do not flush on out-null [38]
 o tool: init progress bar on demand [39]
 o tool_operate: remove call to abort() [23]
 o urlapi: do not keep an internal port string [31]
 o VULN-DISCLOSURE-POLICY.md: issues that should be found by tests are LOW [5]

This release includes the following known bugs:

 See https://curl.se/docs/knownbugs.html

For all changes ever done in curl:

 See https://curl.se/changes.html

Planned upcoming removals include:

 o local crypto implementations
 o NTLM
 o SMB
 o TLS-SRP support

 See https://curl.se/dev/deprecate.html

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

  Alhuda Khan, alhudz, Dan Fandrich, Daniel Stenberg, Ray Satiro,
  renovate[bot], Roger Leigh, Sam James, Samuel Dainard, Stefan Eissing,
  stze on hackerone, Viktor Szakats
  (12 contributors)

References to bug reports and discussions on issues:

 [1] = https://curl.se/bug/?i=22116
 [2] = https://curl.se/bug/?i=22158
 [3] = https://curl.se/bug/?i=22152
 [5] = https://curl.se/bug/?i=22190
 [6] = https://curl.se/bug/?i=22195
 [7] = https://curl.se/bug/?i=22198
 [8] = https://curl.se/bug/?i=22197
 [9] = https://curl.se/bug/?i=22194
 [10] = https://curl.se/bug/?i=22191
 [11] = https://curl.se/bug/?i=22193
 [12] = https://curl.se/bug/?i=22192
 [15] = https://curl.se/bug/?i=22187
 [17] = https://curl.se/bug/?i=22178
 [20] = https://curl.se/bug/?i=22169
 [22] = https://curl.se/bug/?i=22179
 [23] = https://curl.se/bug/?i=22182
 [29] = https://curl.se/bug/?i=22113
 [31] = https://curl.se/bug/?i=22167
 [32] = https://curl.se/bug/?i=22100
 [33] = https://curl.se/bug/?i=22154
 [34] = https://curl.se/bug/?i=22150
 [35] = https://curl.se/bug/?i=22148
 [38] = https://curl.se/bug/?i=22165
 [39] = https://curl.se/bug/?i=22164
 [40] = https://curl.se/bug/?i=22136
 [41] = https://curl.se/bug/?i=22136
 [43] = https://curl.se/bug/?i=22112