I have the following:

FetchContent_Declare(
        lbfgs
        GIT_REPOSITORY https://github.com/foolnotion/lbfgs.git
        GIT_TAG main
)
FetchContent_MakeAvailable(lbfgs)

lbfgs also requires outcome though. So I also tried adding that on my cmake file.

FetchContent_Declare(
        outcome
        GIT_REPOSITORY https://github.com/ned14/outcome.git
        GIT_TAG v2.2.8
)
FetchContent_MakeAvailable(outcome)

I get this output while building though:

CMake Warning (dev) at cmake-build-debug/quickcpplib/repo/cmakelib/QuickCppLibSetupProject.cmake:13 (include):
  Policy CMP0148 is not set: The FindPythonInterp and FindPythonLibs modules
  are removed.  Run "cmake --help-policy CMP0148" for policy details.  Use
  the cmake_policy command to set the policy and suppress this warning.

Call Stack (most recent call first):
  cmake-build-debug/_deps/outcome-src/CMakeLists.txt:51 (include)
This warning is for project developers.  Use -Wno-dev to suppress it.

-- Using cached scan of project outcome headers ...
-- Using cached scan of project outcome tests ...
CMake Warning at cmake-build-debug/quickcpplib/repo/cmakelib/QuickCppLibUtils.cmake:84 (message):
  WARNING: .clang-tidy file found for project outcome, yet clang-tidy not on
  PATH so disabling lint pass
Call Stack (most recent call first):
  cmake-build-debug/quickcpplib/repo/cmakelib/QuickCppLibSetupProject.cmake:205 (indented_message)
  cmake-build-debug/_deps/outcome-src/CMakeLists.txt:51 (include)


-- Missing dependency quickcpplib is NOT installed in cmake packages!
-- Missing dependency quickcpplib is NOT found at /home/jiyoung/Downloads/research/SymbolicRegression/deletmeee/cmake-build-debug/quickcpplib!
-- Superbuilding missing dependency quickcpplib with config Debug, this may take a while ...
-- NOTE: NOT compiling header only library for outcome into a precompiled header due to this project being a dependency of a higher level project
CMake Error at cmake-build-debug/_deps/lbfgs-src/CMakeLists.txt:27 (find_package):
  By not providing "Findoutcome.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "outcome", but
  CMake did not find one.

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

    outcomeConfig.cmake
    outcome-config.cmake

  Add the installation prefix of "outcome" to CMAKE_PREFIX_PATH or set
  "outcome_DIR" to a directory containing one of the above files.  If
  "outcome" provides a separate development package or SDK, be sure it has
  been installed.

How can I install lbfgs using FetchContent?