Netif (Linux): fix unused-result warning (#1340)

Author: apocelipes

src/common/netif/netif_linux.c

@@ -13,7 +13,7 @@ bool ffNetifGetDefaultRouteImpl(char iface[IF_NAMESIZE + 1], uint32_t* ifIndex)
     if (!netRoute) return false;
 
     // skip first line
-    fscanf(netRoute, "%*[^\n]\n");
+    FF_UNUSED(fscanf(netRoute, "%*[^\n]\n"));
 
     unsigned long long destination; //, gateway, flags, refCount, use, metric, mask, mtu,
     while (fscanf(netRoute, "%" FF_STR(IF_NAMESIZE) "s%llx%*[^\n]", iface, &destination) == 2)