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#19117https://github.com/curl/curl/pull/20784#issuecomment-3984318492
Depends-on: fad1ebaecc#20840
Follow-up to 91e06fde1b#20784
Follow-up to 26c39d8df1#20015Closes#20814
8fce3e17e6