libwebsockets: add optional libevent dependency

libevent is supported since 2.3.0

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit e46257264ed773a9c2b94e0e4f0131187a8940ba)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libwebsockets/libwebsockets.mk

@@ -35,6 +35,13 @@ else
 LIBWEBSOCKETS_CONF_OPTS += -DLWS_WITH_LIBEV=OFF
 endif
 
+ifeq ($(BR2_PACKAGE_LIBEVENT),y)
+LIBWEBSOCKETS_DEPENDENCIES += libevent
+LIBWEBSOCKETS_CONF_OPTS += -DLWS_WITH_LIBEVENT=ON
+else
+LIBWEBSOCKETS_CONF_OPTS += -DLWS_WITH_LIBEVENT=OFF
+endif
+
 ifeq ($(BR2_PACKAGE_LIBUV),y)
 LIBWEBSOCKETS_DEPENDENCIES += libuv
 LIBWEBSOCKETS_CONF_OPTS += -DLWS_WITH_LIBUV=ON