libmemif: fix clang compilation errors/warnings

Change-Id: I09444281a932d367162a10b90c3759db71c03350
Signed-off-by: Jakub Grajciar <jgrajcia@cisco.com>
diff --git a/extras/libmemif/src/socket.h b/extras/libmemif/src/socket.h
index a8e9fbc..e079227 100644
--- a/extras/libmemif/src/socket.h
+++ b/extras/libmemif/src/socket.h
@@ -16,7 +16,7 @@
  */
 
 #ifndef _SOCKET_H_
-#define _SOCKET_H
+#define _SOCKET_H_
 
 #include <memif_private.h>