https://bugs.gentoo.org/836708
https://github.com/xdp-project/xdp-tools/pull/309

From c9956abbfbd238bd2eb98c67ea002bfce29063a4 Mon Sep 17 00:00:00 2001
From: Stijn Tintel <stijn@linux-ipv6.be>
Date: Wed, 29 Mar 2023 04:25:06 +0300
Subject: [PATCH] libxdp: fix build on musl

In musl, PATH_MAX is defined in limits.h. Include it in libxdp.c to fix
building systems using musl libc.

libxdp.c: In function 'find_bpffs':
libxdp.c:406:33: error: 'PATH_MAX' undeclared (first use in this function)
  406 |         static char bpf_wrk_dir[PATH_MAX];
      |                                 ^~~~~~~~

Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
--- a/lib/libxdp/libxdp.c
+++ b/lib/libxdp/libxdp.c
@@ -22,6 +22,7 @@
 #include <fcntl.h>
 #include <inttypes.h>
 #include <dirent.h>
+#include <limits.h>
 
 #include <linux/err.h> /* ERR_PTR */
 #include <linux/if_link.h>