Fixed a sloppy common-style declaration.

natm_pcb.c:
Include <sys/socketvar.h> which will be used when M_PCB is declared
in the right place.

sys/netnatm/natm.h

@@ -113,7 +113,7 @@ LIST_HEAD(npcblist, natmpcb);
 
 /* global data structures */
 
-struct npcblist natm_pcbs;		/* global list of pcbs */
+extern struct npcblist natm_pcbs;	/* global list of pcbs */
 extern	struct ifqueue natmintrq;	/* natm packet input queue */
 #define	NATM_STAT
 #ifdef NATM_STAT

sys/netnatm/natm_pcb.c

@@ -41,6 +41,7 @@
 #include <sys/systm.h>
 #include <sys/malloc.h>
 #include <sys/socket.h>
+#include <sys/socketvar.h>
 
 #include <net/if.h>
 
@@ -48,6 +49,8 @@
 
 #include <netnatm/natm.h>
 
+struct npcblist natm_pcbs;
+
 /*
  * npcb_alloc: allocate a npcb [in the free state]
  */