fix preprocessor error introduced in poll.h in last commit

(cherry picked from commit 91a3bd743e91604bde83e9ce1ad3a2e2d4ff0f0f)

include/poll.h

@@ -24,7 +24,7 @@ extern "C" {
 #ifndef POLLMSG
 #define POLLMSG    0x400
 #define POLLRDHUP  0x2000
-#define
+#endif
 
 typedef unsigned long nfds_t;