$NetBSD: patch-aa,v 1.2 2012/05/04 16:11:02 joerg Exp $

libnet_getgre_length is used by different TUs, so it certainly is not inline.
void foo() is different from void foo(void), at least in C.

--- include/libnet/libnet-functions.h.orig	2004-03-25 18:50:48.000000000 +0000
+++ include/libnet/libnet-functions.h
@@ -1429,7 +1429,7 @@ libnet_t *l, libnet_ptag_t ptag);
  * @param ptag protocol tag to modify an existing header, 0 to build a new one
  * @return protocol tag value on success, -1 on error
  */
-inline u_int32_t
+u_int32_t
 libnet_getgre_length(u_int16_t fv);
 
 /**
@@ -1837,7 +1837,7 @@ libnet_cq_find_by_label(char *label);
  * member context.
  */
 void
-libnet_cq_destroy();
+libnet_cq_destroy(void);
 
 /**
  * [Context Queue] 
@@ -1859,7 +1859,7 @@ libnet_cq_destroy();
  * @return the head of the context queue
  */
 libnet_t *
-libnet_cq_head();
+libnet_cq_head(void);
 
 /**
  * [Context Queue] 
@@ -1867,7 +1867,7 @@ libnet_cq_head();
  * @return 1 if at the end of the context queue, 0 otherwise
  */
 int
-libnet_cq_last();
+libnet_cq_last(void);
 
 /**
  * [Context Queue] 
@@ -1875,7 +1875,7 @@ libnet_cq_last();
  * @reutrn the next context from the context queue
  */
 libnet_t *
-libnet_cq_next();
+libnet_cq_next(void);
 
 /**
  * [Context Queue] 
@@ -1883,7 +1883,7 @@ libnet_cq_next();
  * @return the number of libnet contexts currently in the queue
  */
 u_int32_t
-libnet_cq_size();
+libnet_cq_size(void);
 
 /**
  * [Diagnostic]