MINOR: inet: report the faulty interface name in "bind" errors

When a "bind ... interface foo" statement fails, let's report the
interface name in the error message to help locating it in the file.
diff --git a/src/sock_inet.c b/src/sock_inet.c
index fb69981..1402dd0 100644
--- a/src/sock_inet.c
+++ b/src/sock_inet.c
@@ -362,7 +362,7 @@
 		if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE,
 		               rx->settings->interface,
 		               strlen(rx->settings->interface) + 1) == -1) {
-			memprintf(errmsg, "cannot bind receiver to device (%s)", strerror(errno));
+			memprintf(errmsg, "cannot bind receiver to device '%s' (%s)", rx->settings->interface, strerror(errno));
 			err |= ERR_WARN;
 		}
 	}