diff --git a/configure.in b/configure.in
index f512c95fee59b097acdbaae2c3b0e4fcea363d39..e8b4ba4d1aa811d938021edb0363de04a9110a4f 100644
--- a/configure.in
+++ b/configure.in
@@ -5,6 +5,8 @@ dnl Process this file with autoconf to produce a configure script.
 
 AC_INIT(arcfour.c)
 
+AC_PREREQ(2.50)
+
 AM_INIT_AUTOMAKE(nettle, 1.5)
 
 AM_CONFIG_HEADER(config.h)