cmake LWS_HAVE_RTA_PREF examples

warmcat/libwebsockets CMakeLists.txt :818 

CHECK_C_SOURCE_COMPILES("#include <linux/rtnetlink.h>
	int main(void) {
		int test = RTA_PREF;
		return 0;
	}" LWS_HAVE_RTA_PREF)

c-jimenez/open-ocpp 3rdparty/libwebsockets/CMakeLists.txt :722 

CHECK_C_SOURCE_COMPILES("#include <linux/rtnetlink.h>
	int main(void) {
		int test = RTA_PREF;
		return 0;
	}" LWS_HAVE_RTA_PREF)

fluffos/fluffos src/thirdparty/libwebsockets/CMakeLists.txt :705 

CHECK_C_SOURCE_COMPILES("#include <linux/rtnetlink.h>
	int main(void) {
		int test = RTA_PREF;
		return 0;
	}" LWS_HAVE_RTA_PREF)