spdlog is now private

[stephen-derosa]

Building against release 0.3.2 causes error:

-- [download 99% complete]
-- [download 100% complete]
-- LiveKitSDK: extracting /home/runner/work/cpp-example-collection/cpp-example-collection/build/_downloads/livekit-sdk-linux-x64-0.3.2.tar.gz
-- LiveKitSDK: using SDK at /home/runner/work/cpp-example-collection/cpp-example-collection/build/_deps/livekit-sdk/livekit-sdk-linux-x64-0.3.2
CMake Error at /usr/local/share/cmake-3.31/Modules/CMakeFindDependencyMacro.cmake:76 (find_package):
  By not providing "Findspdlog.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "spdlog", but
  CMake did not find one.

  Could not find a package configuration file provided by "spdlog" with any
  of the following names:

    spdlogConfig.cmake
    spdlog-config.cmake

  Add the installation prefix of "spdlog" to CMAKE_PREFIX_PATH or set
  "spdlog_DIR" to a directory containing one of the above files.  If "spdlog"
  provides a separate development package or SDK, be sure it has been
  installed.
Call Stack (most recent call first):
  build/_deps/livekit-sdk/livekit-sdk-linux-x64-0.3.2/lib/cmake/LiveKit/LiveKitConfig.cmake:28 (find_dependency)
  CMakeLists.txt:38 (find_package)


-- Configuring incomplete, errors occurred!

This MR adds a build against an external project in CI to test cmake linking. It depends on this work

I brought in the github action client build commit into this MR to include the test of the fix!

[Copilot]

Pull request overview

This PR changes the CMake configuration for the vendored spdlog dependency so that spdlog’s own install rules are enabled when fetched via FetchContent on macOS/Linux.

Changes:

• Enable SPDLOG_INSTALL for the vendored spdlog build (OFF → ON).

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[xianshijing-lk]

lgtm, thanks