[monitoring-plugins] Set autoconf prerequisite version to 2.64

[RincewindsHat]

 Module: monitoring-plugins
 Branch: master
 Commit: 393bd16d2e21833236f65fb330fe848eb45f742d
 Author: RincewindsHat <12514511+RincewindsHat at users.noreply.github.com>
   Date: Tue Jan 31 14:46:37 2023 +0100
    URL: https://www.monitoring-plugins.org/repositories/monitoring-plugins/commit/?id=393bd16

Set autoconf prerequisite version to 2.64

---

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

diff --git a/configure.ac b/configure.ac
index 87a84a0..0c7169e 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])