set(CORE_SRC core.c ) list(TRANSFORM CORE_SRC PREPEND ${CMAKE_CURRENT_LIST_DIR}/) include(FetchContent) find_package(OpenSSL REQUIRED) add_library(pigeon-core ${CORE_SRC}) target_include_directories(pigeon-core PUBLIC ${CMAKE_CURRENT_LIST_DIR}/src) target_link_libraries(pigeon-core OpenSSL::SSL)