diff --git a/configure.in b/configure.in
index 8e73c254..75d4bac6 100644
--- a/configure.in
+++ b/configure.in
@@ -2,6 +2,7 @@ dnl Process this file with autoconf to produce a configure script.
 AC_INIT(reduce.c)
 AM_INIT_AUTOMAKE(bison,1.26)
 AM_CONFIG_HEADER(config.h:config.hin)
+AC_PREREQ(2.13)
 
 dnl Checks for programs.
 AC_PROG_CC
@@ -27,6 +28,6 @@ AM_C_PROTOTYPES
 
 dnl Checks for library functions.
 AC_FUNC_ALLOCA
-AC_CHECK_FUNCS(setlocale)
+AC_CHECK_FUNCS(mkstemp setlocale)
 
 AC_OUTPUT(Makefile)