if (ETH_STACK STREQUAL "ETHERLIB") set(ETH_STACK_SRC ethernet_etherlib.c ethernet_etherlib.h ) elseif(ETH_STACK STREQUAL "LWIP") set(ETH_STACK_SRC ethernet_lwip.c) else() message("No Ethernet stack was defined!") endif() if (ETH_STACK) message("Ethernet stack: " ${ETH_STACK}) endif() target_sources( ${CMAKE_PROJECT_NAME} PUBLIC ${ETH_STACK_SRC} )