From 0843d0c5b289de06fc098e847fb95d6a02ad6fb3 Mon Sep 17 00:00:00 2001
From: Robert Nagy <robert@openbsd.org>
Date: Wed, 15 Dec 2021 13:33:09 +0100
Subject: [PATCH] avoid linking an undefined function, sysfs is linux only
 (#474)

---
 src/first_network_device.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/first_network_device.c b/src/first_network_device.c
index 3d06217..3af43cc 100644
--- a/src/first_network_device.c
+++ b/src/first_network_device.c
@@ -25,6 +25,7 @@
 #define LOOPBACK_DEV "lo"
 #endif
 
+#if defined(__linux__)
 static bool sysfs_devtype(char *dest, size_t n, const char *ifnam) {
     FILE *fp;
     char buf[1024];
@@ -54,6 +55,7 @@ static bool sysfs_devtype(char *dest, size_t n, const char *ifnam) {
     fclose(fp);
     return true;
 }
+#endif
 
 static bool is_virtual(const char *ifname) {
     char path[1024];
@@ -131,7 +133,7 @@ static net_type_t iface_type(const char *ifname) {
         close(s);
         return NET_TYPE_ETHERNET;
     }
-#else
+#elif defined(__linux__)
     char devtype[32];
 
     if (!sysfs_devtype(devtype, sizeof(devtype), ifname))