ibss: remove _POSIX_SOURCE

It doesn't appear to be necessary and is causing warnings about
struct addrinfo.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/ibss.c b/ibss.c
index beb74e5..2b0b495 100644
--- a/ibss.c
+++ b/ibss.c
@@ -1,16 +1,7 @@
-#ifndef _POSIX_SOURCE
-#define _POSIX_SOURCE
-#endif
 #include <errno.h>
 #include <string.h>
 #include <strings.h>
 
-#include <netlink/genl/genl.h>
-#include <netlink/genl/family.h>
-#include <netlink/genl/ctrl.h>
-#include <netlink/msg.h>
-#include <netlink/attr.h>
-
 #include "nl80211.h"
 #include "iw.h"