add SO_ getsockopt options from linux v4.13

SCM_TIMESTAMPING_PKTINFO is new in aad9c8c470f2a8321a99eb053630ce0e199558d6
SO_PEERGROUPS is new in 28b5ba2aa0f55d80adb2624564ed2b170c19519e

include/sys/socket.h

@@ -228,6 +228,8 @@ struct linger {
 #define SO_MEMINFO              55
 #define SO_INCOMING_NAPI_ID     56
 #define SO_COOKIE               57
+#define SCM_TIMESTAMPING_PKTINFO 58
+#define SO_PEERGROUPS           59
 
 #ifndef SOL_SOCKET
 #define SOL_SOCKET      1