Can not build with curl 8.12

[owent]

Describe your environment

Can not build with libcurl 8.12.

[ 99%] Built target func_otlp_grpc
/usr/bin/gmake  -f functional/otlp/CMakeFiles/func_otlp_http.dir/build.make functional/otlp/CMakeFiles/func_otlp_http.dir/depend
gmake[2]: Entering directory '/home/runner/work/cmake-toolset/cmake-toolset/test/build_jobs_dir/_deps/opentelemetry_cpp-v1.19.0/linux-x86_64-gnu-13'
cd /home/runner/work/cmake-toolset/cmake-toolset/test/build_jobs_dir/_deps/opentelemetry_cpp-v1.19.0/linux-x86_64-gnu-13 && /usr/local/bin/cmake -E cmake_depends "Unix Makefiles" /home/runner/work/cmake-toolset/cmake-toolset/test/third_party/packages/opentelemetry-cpp-v1.19.0 /home/runner/work/cmake-toolset/cmake-toolset/test/third_party/packages/opentelemetry-cpp-v1.19.0/functional/otlp /home/runner/work/cmake-toolset/cmake-toolset/test/build_jobs_dir/_deps/opentelemetry_cpp-v1.19.0/linux-x86_64-gnu-13 /home/runner/work/cmake-toolset/cmake-toolset/test/build_jobs_dir/_deps/opentelemetry_cpp-v1.19.0/linux-x86_64-gnu-13/functional/otlp /home/runner/work/cmake-toolset/cmake-toolset/test/build_jobs_dir/_deps/opentelemetry_cpp-v1.19.0/linux-x86_64-gnu-13/functional/otlp/CMakeFiles/func_otlp_http.dir/DependInfo.cmake "--color="
gmake[2]: Leaving directory '/home/runner/work/cmake-toolset/cmake-toolset/test/build_jobs_dir/_deps/opentelemetry_cpp-v1.19.0/linux-x86_64-gnu-13'
/usr/bin/gmake  -f functional/otlp/CMakeFiles/func_otlp_http.dir/build.make functional/otlp/CMakeFiles/func_otlp_http.dir/build
gmake[2]: Entering directory '/home/runner/work/cmake-toolset/cmake-toolset/test/build_jobs_dir/_deps/opentelemetry_cpp-v1.19.0/linux-x86_64-gnu-13'
[100%] Linking CXX executable func_otlp_http
cd /home/runner/work/cmake-toolset/cmake-toolset/test/build_jobs_dir/_deps/opentelemetry_cpp-v1.19.0/linux-x86_64-gnu-13/functional/otlp && /usr/local/bin/cmake -E cmake_link_script CMakeFiles/func_otlp_http.dir/link.txt --verbose=1
/usr/bin/ld: cannot find -lcares: No such file or directory
/usr/bin/ld: cannot find -lnghttp2: No such file or directory
collect2: error: ld returned 1 exit status

[marcalff]

There are quite a few changes related to CMake in curl 8.12.1:

• https://curl.se/ch/8.12.1.html

I wonder if the issue is with the curl 8.12 install or with opentelemetry-cpp

[owent]

The issue arises with curl installation when exporting CMake targets, but no related information is mentioned in the curl 8.12 changelog. vcpkg uses a patch (https://github.com/microsoft/vcpkg/blob/2025.01.13/ports/curl/dependencies.patch) to replace all -lXXX with CMake targets to solve this issue. However, since we are not a build system, we cannot modify curl's build script. #3272 attempts to handle this problem for otel-cpp builds but does not export the link flags.

BTW: There is a problem about curl's target name when using official exporting. #3272 also fixes it.