add AF_XDP to sys/socket.h from linux v4.18

new address family and related macros were added in linux commit
68e8b849b221b37a78a110a0307717d45e3593a0

include/sys/socket.h

@@ -109,7 +109,8 @@ struct linger {
 #define PF_KCM          41
 #define PF_QIPCRTR      42
 #define PF_SMC          43
-#define PF_MAX          44
+#define PF_XDP          44
+#define PF_MAX          45
 
 #define AF_UNSPEC       PF_UNSPEC
 #define AF_LOCAL        PF_LOCAL
@@ -158,6 +159,7 @@ struct linger {
 #define AF_KCM          PF_KCM
 #define AF_QIPCRTR      PF_QIPCRTR
 #define AF_SMC          PF_SMC
+#define AF_XDP          PF_XDP
 #define AF_MAX          PF_MAX
 
 #ifndef SO_DEBUG
@@ -265,6 +267,7 @@ struct linger {
 #define SOL_NFC         280
 #define SOL_KCM         281
 #define SOL_TLS         282
+#define SOL_XDP         283
 
 #define SOMAXCONN       128