curl-curl/docs
Viktor Szakats 38107d3354
configure: fix --with-ngtcp2=<path> option for crypto libs
ngtcp2 1.14.0 added module dependencies to `ngtcp2_crypto_*.pc` files.
This broke certain build cases in curl, because configure was is
querying pkg-config modules by setting `PKG_CONFIG_LIBDIR` to the
directory specified via `--with-*=` options, including `--with-ngtcp2=`.
Setting `PKG_CONFIG_LIBDIR` tells pkg-config (and pkgconf) to ignore
system locations. This caused that `ngtcp2_crypto_gnutls.pc` could no
longer find its indirect dependencies, if those were present at system
locations (where they typically are). Another fallout was BoringSSL,
because it does not provide `openssl.pc` on its own, and successful
detection relied on finding a non-BoringSSL copy, typically at a system
location (also fixed in ngtcp2 main branch).

Fix `ngtcp2_crypto_*` detections to not touch `PKG_CONFIG_LIBDIR` and
instead prepend `<path>` set via `--with-ngtcp2=` to `PKG_CONFIG_PATH`.
This ensures to pick up any dependent modules from system locations.

Note the side-effect is that potentially undesired modules may be
detected this way from system locations, i.e. it makes this particular
detection less "hermetic" than the rest used in curl configure.

(Configurations using a bare `--with-ngtcp2` with no path were not
affected, and served as a workaround before this patch. It remains a
valid way of configuration after.)

Both `pkgconf` and `pkg-config` use this logic to calculate their search
directory list:
```pseudo
search = {}
if PKG_CONFIG_PATH is set
  search += PKG_CONFIG_PATH
endif
if PKG_CONFIG_LIBDIR is set (even if empty)
  search += PKG_CONFIG_LIBDIR
else
  search += built-in-pkg-config-dirs
endif
```

Refs:
https://github.com/curl/curl/pull/18028/commits (earlier attempt. Failed due to using `PKG_CONFIG_DIR` instead of the correct `PKG_CONFIG_PATH`)
c0874ce824
https://man.archlinux.org/man/pkgconf.1.en
https://manpages.debian.org/unstable/pkgconf/pkgconf.1.en.html
https://manpages.debian.org/unstable/pkg-config/pkg-config.1.en.html
10e27fd63c

Bug: https://github.com/curl/curl/pull/18022#issuecomment-3120587041
Bug: https://github.com/ngtcp2/ngtcp2/pull/1689#issuecomment-3120593664
Follow-up to 04d90b5deb #20931
Follow-up to 3c64ffaff4 #18415 #18188
Follow-up to 99500660af #18028 #18022

Closes #20920
2026-03-17 14:37:53 +01:00
..
cmdline-opts curl_get_line: fix potential infinite loop when filename is a directory 2026-03-16 11:54:43 +01:00
examples cmake: add CURL_GCC_ANALYZER option, enable in CI, fix/silence 2026-03-16 11:49:34 +01:00
internals badwords: avoid 'simply' 2026-03-10 19:34:06 +01:00
libcurl curl_get_line: fix potential infinite loop when filename is a directory 2026-03-16 11:54:43 +01:00
tests docs: minor wording tweaks 2026-03-11 08:46:01 +01:00
.gitignore docs: add RELEASE-TOOLS.md.dist to .gitignore 2024-07-01 22:49:55 +02:00
ALTSVC.md docs: fold long lines 2025-12-11 11:42:28 +01:00
BINDINGS.md docs: some nitpicks 2026-02-27 23:05:37 +01:00
BUG-BOUNTY.md BUG-BOUNTY.md: minor rephrase to say there is no bug bounty 2026-03-10 17:34:08 +01:00
BUGS.md docs: avoid using the word 'magic' 2026-03-03 15:32:13 +01:00
CIPHERS-TLS12.md docs: update CIPHERS.md 2024-08-12 23:35:56 +02:00
CIPHERS.md docs: avoid starting sentences with However, 2026-03-07 23:49:11 +01:00
CMakeLists.txt tests: move test docs into /docs 2025-05-28 15:00:03 +02:00
CODE_OF_CONDUCT.md tidy-up: Markdown, clang-format nits 2026-01-22 23:44:47 +01:00
CODE_REVIEW.md docs: fix broken link in CODE_REVIEW.md 2025-06-21 10:32:06 +02:00
CONTRIBUTE.md badwords: avoid 'simply' 2026-03-10 19:34:06 +01:00
curl-config.md docs: minor edits to please the new spellchecker regime 2025-02-27 13:15:21 +01:00
CURL-DISABLE.md build: add build-level CURL_DISABLE_TYPECHECK options 2025-11-21 13:48:35 +01:00
CURLDOWN.md stop using the word 'just' 2026-03-03 15:30:22 +01:00
DEPRECATE.md DEPRECATE.md: SMB and NTLM become build-time opt-in 2026-03-07 14:56:08 +01:00
DISTROS.md docs: add LibreELEC to DISTROS.md 2026-01-26 12:12:05 -08:00
EARLY-RELEASE.md stop using the word 'just' 2026-03-03 15:30:22 +01:00
ECH.md ECH.md: replace double-backticks with single ones 2026-03-16 14:24:25 +01:00
EXPERIMENTAL.md docs/EXPERIMENTAL.md: add a mention of HTTPSRR as experimental 2025-01-16 19:41:42 +01:00
FAQ.md docs/lib: fix typos 2026-03-16 10:43:24 +01:00
FEATURES.md tidy-up: miscellaneous 2026-01-20 12:37:56 +01:00
GOVERNANCE.md docs: avoid starting sentences with However, 2026-03-07 23:49:11 +01:00
HELP-US.md tidy-up: miscellaneous 2026-01-15 13:06:13 +01:00
HISTORY.md docs: replace instances of the vague qualifier 'quite' 2026-03-07 23:52:50 +01:00
HSTS.md tidy-up: miscellaneous 2026-01-20 12:37:56 +01:00
HTTP3.md configure: fix --with-ngtcp2=<path> option for crypto libs 2026-03-17 14:37:53 +01:00
HTTP-COOKIES.md stop using the word 'just' 2026-03-03 15:30:22 +01:00
HTTPSRR.md badwords: avoid 'simply' 2026-03-10 19:34:06 +01:00
INFRASTRUCTURE.md BUG-BOUNTY.md: we stop the bug-bounty end of Jan 2026 2026-01-26 08:26:28 +01:00
INSTALL INSTALL: converted to markdown => INSTALL.md 2016-10-21 15:57:29 +02:00
INSTALL-CMAKE.md cmake: add CURL_GCC_ANALYZER option, enable in CI, fix/silence 2026-03-16 11:49:34 +01:00
INSTALL.md configure: add option to trace pkg-config detection details 2026-03-16 11:31:01 +01:00
INTERNALS.md clang-tidy: replace comma-separated string with list in config 2026-02-19 16:27:08 +01:00
IPFS.md stop using the word 'just' 2026-03-03 15:30:22 +01:00
KNOWN_BUGS.md docs: avoid starting sentences with However, 2026-03-07 23:49:11 +01:00
KNOWN_RISKS.md stop using the word 'just' 2026-03-03 15:30:22 +01:00
MAIL-ETIQUETTE.md badwords: avoid 'simply' 2026-03-10 19:34:06 +01:00
Makefile.am tidy-up: miscellaneous 2026-01-15 13:06:13 +01:00
MANUAL.md badwords: avoid 'simply' 2026-03-10 19:34:06 +01:00
mk-ca-bundle.md stop using the word 'just' 2026-03-03 15:30:22 +01:00
options-in-versions tool_getparam: add --knownhosts 2025-10-06 13:41:22 +02:00
README.md reuse: add copyright + license info to individual docs/*.md files 2024-03-31 12:01:18 +02:00
RELEASE-PROCEDURE.md RELEASE-PROCEDURE.md: update future release dates 2026-01-26 12:28:25 +01:00
ROADMAP.md CI: add whitespace checker 2024-06-27 13:33:30 +02:00
runtests.md badwords: avoid 'simply' 2026-03-10 19:34:06 +01:00
RUSTLS.md tidy-up: URLs 2025-09-23 00:34:46 +02:00
SECURITY-ADVISORY.md stop using the word 'just' 2026-03-03 15:30:22 +01:00
SPONSORS.md BUG-BOUNTY.md: we stop the bug-bounty end of Jan 2026 2026-01-26 08:26:28 +01:00
SSL-PROBLEMS.md tidy-up: Markdown, clang-format nits 2026-01-22 23:44:47 +01:00
SSLCERTS.md tidy-up: miscellaneous 2025-12-12 04:18:48 +01:00
testcurl.md tidy-up: Markdown, clang-format nits 2026-01-22 23:44:47 +01:00
THANKS THANKS: add contributors from 8.19.0 release 2026-03-11 07:46:12 +01:00
THANKS-filter THANKS-filter: update with a new entry 2026-03-09 11:35:19 +01:00
TheArtOfHttpScripting.md badwords: avoid 'simply' 2026-03-10 19:34:06 +01:00
TODO.md docs: avoid starting sentences with However, 2026-03-07 23:49:11 +01:00
URL-SYNTAX.md docs: avoid starting sentences with However, 2026-03-07 23:49:11 +01:00
VERSIONS.md VERSIONS: add 8.19.0 2026-03-11 07:46:12 +01:00
VULN-DISCLOSURE-POLICY.md BUG-BOUNTY.md: minor rephrase to say there is no bug bounty 2026-03-10 17:34:08 +01:00
wcurl.md badwords: avoid 'simply' 2026-03-10 19:34:06 +01:00

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If you would rather see the rendered version of the documentation, check out the curl website's documentation section for general curl stuff or the libcurl section for libcurl related documentation.