Change #261911

Comments

cmake: add CMake Config-based dependency detection

After limiting `find_package()`/`find_dependency()` calls to curl local
Find modules via the `MODULES` keyword, it became possible to detect
dependencies via CMake Configs from within those local Find modules, by
calling `find_package()` again with the `CONFIG` keyword. This patch
implements this. Then maps detection results to the result variables and
curl-specific imported targets the rest of the build expects.

Also honor recently introduced `*_USE_STATIC_LIBS` (experimental) flags
to map to the static target when requested.

This adds CMake Configs as an alternative to the existing `pkg-config`
and `find_path()`/`find_library()` auto-detection methods.

Enabled by default for MSVC, outside vcpkg and when not cross-building.
To enable for other cases, or override the default, you can use
`-DCURL_USE_CMAKECONFIG=ON` or `OFF`.

When enabled, Config detection happens after `pkg-config` and before
`find_path()`/`find_library()`. Using CMake's built-in options, you may
also manually point to the absolute directory holding Config files:

`Libssh2_DIR`, `MbedTLS_DIR`, `NGHTTP2_DIR`, `NGHTTP3_DIR`,
`NGTCP2_DIR` v1.19.0+ (with non-fork OpenSSL only), `Zstd_DIR` v1.4.5+

E.g. `-DMbedTLS_DIR=/path/to/mbedtls/lib/cmake/MbedTLS`

These dependencies typically need to be built with CMake to support
this.

Tagged as experimental.

Refs:
#20013 #19156 #19117
https://github.com/curl/curl/pull/20784#issuecomment-3984318492

Depends-on: fad1ebaecc0c489d38c0a9a155f63fdfd9086907 #20840
Follow-up to 91e06fde1b520bc29c7996749734451e03cd549f #20784
Follow-up to 26c39d8df182a63d28d81ed2b044e6a343519d1a #20015

Closes #20814

Changed files

• .github/workflows/configure-vs-cmake.yml
• CMake/FindLibssh2.cmake
• CMake/FindMbedTLS.cmake
• CMake/FindNGHTTP2.cmake
• CMake/FindNGHTTP3.cmake
• CMake/FindNGTCP2.cmake
• CMake/FindZstd.cmake
• CMake/curl-config.in.cmake
• CMakeLists.txt
• docs/INSTALL-CMAKE.md
• tests/cmake/CMakeLists.txt