include(FetchContent) set(HTTPLIB_REQUIRE_OPENSSL ON CACHE BOOL "" FORCE) set(HTTPLIB_USE_OPENSSL_IF_AVAILABLE ON CACHE BOOL "" FORCE) FetchContent_Declare(httplib GIT_REPOSITORY https://github.com/yhirose/cpp-httplib.git GIT_TAG v0.46.0) FetchContent_MakeAvailable(httplib)