diff --git a/acconfig.h b/acconfig.h
index b6dba9439..e761eb82e 100644
--- a/acconfig.h
+++ b/acconfig.h
@@ -115,6 +115,12 @@
 /* define if the system is missing a prototype for strtok_r() */
 #undef NEED_HSTRERROR_PROTO
 
+/* define if the system is missing a prototype for snprintf() */
+#undef NEED_SNPRINTF_PROTO
+
+/* define if the system is missing a prototype for vsnprintf() */
+#undef NEED_VSNPRINTF_PROTO
+
 /* Define this if your `struct tm' has a field `tm_gmtoff' */
 #undef HAVE_STRUCT_TM_TM_GMTOFF