cmake_minimum_required(VERSION 3.26) project(getopt) add_library( getopt ${CMAKE_CURRENT_LIST_DIR}/src/getopt.c ${CMAKE_CURRENT_LIST_DIR}/src/getopt1.c ) target_include_directories( getopt PUBLIC ${CMAKE_CURRENT_LIST_DIR}/include) # we are requring string.h here include(CheckIncludeFile) check_include_file("string.h" HAVE_STRING_HEADER_FILE) if (HAVE_STRING_HEADER_FILE) target_compile_definitions( getopt PRIVATE HAVE_STRING_H=1 ) endif()