[monitoring-plugins] Update needed autoconf version

[RincewindsHat]

 Module: monitoring-plugins
 Branch: update_gnulib_2021
 Commit: ddbc9b78e22f9c9c4a323ba69e9a2e3ca41a91f4
 Author: RincewindsHat <12514511+RincewindsHat at users.noreply.github.com>
   Date: Wed Nov 17 01:07:05 2021 +0100
    URL: https://www.monitoring-plugins.org/repositories/monitoring-plugins/commit/?id=ddbc9b7

Update needed autoconf version

---

 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 8c5ca70..d95cc64 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,5 +1,5 @@
 dnl Process this file with autoconf to produce a configure script.
-AC_PREREQ(2.59)
+AC_PREREQ(2.64)
 AC_INIT(monitoring-plugins,2.3git)
 AC_CONFIG_SRCDIR(NPTest.pm)
 AC_CONFIG_FILES([gl/Makefile])