dnl Define the input and output configuration header file.
AC_CONFIG_HEADER([config.h])
-dnl Demand at least version 2.13 of autoconf
-AC_PREREQ(2.13)
+dnl Demand at least version 2.50 of autoconf
+AC_PREREQ(2.50)
dnl Find out what type of system we are
AC_CANONICAL_HOST