Author: Daniel Leidert <dleidert@debian.org>
Description: Fix FTBFS with -Werror=format-security.

--- a/url.c
+++ b/url.c
@@ -61,7 +61,7 @@
 
   rc = idn2_lookup_u8(s, (uint8_t**)&p, IDN2_NFC_INPUT);
   if (rc == IDN2_OK) return p;
-  warnx(idn2_strerror(rc));
+  warnx("%s", idn2_strerror(rc));
   return newstring(s);
 #elif HAVE_LIBIDN
   string p;