esp-idf/components/asio/CMakeLists.txt

if(NOT CONFIG_LWIP_IPV6 AND NOT CMAKE_BUILD_EARLY_EXPANSION)
    # note: the component is still included in the build so it can become visible again in config
    # without needing to re-run CMake. However no source or header files are built.
    message(STATUS "IPV6 support is disabled so the asio component will not be built")
    idf_component_register()
    return()
endif()

set(asio_sources "asio/asio/src/asio.cpp")

if(CONFIG_ASIO_SSL_SUPPORT)
    if(CONFIG_ASIO_USE_ESP_OPENSSL)
        list(APPEND asio_sources
                "port/src/asio_ssl_impl.cpp"
                "port/mbedtls/src/mbedtls_context.cpp"
                "port/mbedtls/src/mbedtls_engine.cpp")
        set(asio_priv_includes "port/mbedtls/include")
    endif()

    if(CONFIG_ASIO_USE_ESP_WOLFSSL)
        list(APPEND asio_sources
                "asio/asio/src/asio_ssl.cpp")
    endif()
endif()

idf_component_register(SRCS ${asio_sources}
                    INCLUDE_DIRS "asio/asio/include" "port/include"
                    PRIV_INCLUDE_DIRS ${asio_priv_includes}
                    REQUIRES lwip)

if(CONFIG_ASIO_SSL_SUPPORT)
    if(CONFIG_ASIO_USE_ESP_WOLFSSL)
        idf_component_get_property(wolflib esp-wolfssl COMPONENT_LIB)
        idf_component_get_property(wolfdir esp-wolfssl COMPONENT_DIR)

        target_link_libraries(${COMPONENT_LIB} PUBLIC ${wolflib})
        target_include_directories(${COMPONENT_LIB} PUBLIC ${wolfdir}/wolfssl/wolfssl)
    endif()

    if(CONFIG_ASIO_USE_ESP_OPENSSL)
        idf_component_get_property(mbedtls mbedtls COMPONENT_LIB)
        target_link_libraries(${COMPONENT_LIB} PUBLIC ${mbedtls})
    endif()
endif()