autoconf: bump AC_PREREQ to 2.64

The acinclude.m4 uses AS_VAR_APPEND macro. This marco is introduced in 2.64[1], hence we bump AC_PREREQ to 2.64 to avoid undefined marco on 2.63 autoconf.

[1] https://lists.gnu.org/archive/html/autoconf/2009-07/msg00079.html

Signed-off-by: Huáng Jùnliàng <i@jhuang.me>
Signed-off-by: Allan McRae <allan@archlinux.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/configure.ac b/configure.ac
index e382c50a..a8c526e3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,7 +1,7 @@
 #                                               -*- Autoconf -*-
 # Process this file with autoconf to produce a configure script.
 # Minimum version of autoconf required
-AC_PREREQ(2.62)
+AC_PREREQ(2.64)
 
 # UPDATING VERSION NUMBERS FOR RELEASES
 #