diff -up lbzip2-b6dc48a7b9bfe6b340ed1f6d72133608ad57144b/configure.ac.orig lbzip2-b6dc48a7b9bfe6b340ed1f6d72133608ad57144b/configure.ac
--- lbzip2-b6dc48a7b9bfe6b340ed1f6d72133608ad57144b/configure.ac.orig	2018-12-27 01:44:09.000000000 +0100
+++ lbzip2-b6dc48a7b9bfe6b340ed1f6d72133608ad57144b/configure.ac	2020-09-19 22:42:14.239366829 +0200
@@ -16,7 +16,7 @@
 
 dnl TODO: check for GCC builtins: expect, prefetch, ctz, ctzl, ctzll
 
-AC_PREREQ([2.63])
+AC_PREREQ([2.64])
 AC_INIT([lbzip2], [2.5])
 
 AC_CONFIG_SRCDIR([src/main.c])