Remove pthread.h include from netdb.h

- It is not needed in the .h, and makes gawk build fail.

headers/posix/netdb.h

@@ -95,8 +95,6 @@
 #include <netinet/in.h>
 #include <stdio.h>
 
-#include <pthread.h>
-
 #ifndef _PATH_NETWORKS
 #define	_PATH_NETWORKS	"/etc/networks"
 #endif

src/kits/network/netresolv/irs/getprotoent.c

@@ -35,6 +35,7 @@ __RCSID("$NetBSD: getprotoent.c,v 1.12 2008/04/28 20:23:00 martin Exp $");
 #endif /* LIBC_SCCS and not lint */
 
 #include <netdb.h>
+#include <pthread.h>
 
 #include "protoent.h"