esp-idf/examples/protocols/coap_client/main/CMakeLists.txt

# Embed CA, certificate & key directly into binary
idf_component_register(SRCS "coap_client_example_main.c"
                    INCLUDE_DIRS "."
                    EMBED_TXTFILES certs/coap_ca.pem certs/coap_client.crt certs/coap_client.key)