From: Khem Raj <raj.khem@gmail.com>
Date: Tue, 24 Jun 2026 00:00:00 +0000
Subject: [PATCH] libdnet: fix PF_PACKET conftest nested function

The bundled libdnet-stripped AC_DNET_LINUX_PF_PACKET check used
"int foo() { return ETH_P_ALL; }" as the AC_TRY_COMPILE body, which the
generated configure places inside main(). clang rejects nested function
definitions ("function definition is not allowed here"), so the check
fails and configure aborts with "Ethernet support not found". Use a plain
expression statement that still references ETH_P_ALL. Patch both the macro
source and the shipped configure.

Upstream-Status: Pending

Signed-off-by: Khem Raj <raj.khem@gmail.com>
---
--- a/libdnet-stripped/m4/acinclude.m4
+++ b/libdnet-stripped/m4/acinclude.m4
@@ -149,7 +149,7 @@
     [AC_MSG_CHECKING(for Linux PF_PACKET sockets)
     AC_TRY_COMPILE([#include <netpacket/packet.h>
                     #include <linux/if_ether.h>],
-                   [int foo() { return ETH_P_ALL; }],
+                   [(void) ETH_P_ALL;],
     ac_cv_dnet_linux_pf_packet=yes,
     ac_cv_dnet_linux_pf_packet=no)
     AC_MSG_RESULT($ac_cv_dnet_linux_pf_packet)
--- a/libdnet-stripped/configure
+++ b/libdnet-stripped/configure
@@ -15219,7 +15219,7 @@
 int
 main (void)
 {
-int foo() { return ETH_P_ALL; }
+(void) ETH_P_ALL;
   ;
   return 0;
 }