compel: plugins,fds -- Add missing headers into uapi

This plugin is all about sending scm-s over unix sockets,
so having this stuff there is helpful.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

compel/plugins/include/uapi/plugin-fds.h

@@ -5,6 +5,8 @@
 #ifndef __COMPEL_PLUGIN_FDS_H__
 #define __COMPEL_PLUGIN_FDS_H__
 
+#include <sys/un.h>
+
 #include "common/scm.h"
 
 static inline int send_fd(int sock, struct sockaddr_un *saddr, int saddr_len, int fd)