Prevent namespace pollution in use-land by putting everything used only in

kernel (softc and such) under #ifdef _KERNEL.

Submitted by:   bde

sys/net/if_gre.h

@@ -41,6 +41,7 @@
 #define _NET_IF_GRE_H
 
 #include <sys/ioccom.h>
+#ifdef _KERNEL
 #include <sys/queue.h>
 
 struct gre_softc {
@@ -141,6 +142,8 @@ struct mobip_h {
 
 #define	GRE_TTL	30
 
+#endif /* _KERNEL */
+
 /* 
  * ioctls needed to manipulate the interface 
  */