Update configure to handle aarch64 architecture

[slayoo]

Migrated from: https://sourceforge.net/p/blitz/bugs/53/

As reported by @sergiopasra:

The configure script in blitz does nor support ARM aarch64 architecture. The support for this architecture was added to autoconf 2.69, whereas blitz's configure was created with autoconf 2.68. Please recreate configure with autoconf >= 2.69

https://bugzilla.redhat.com/show_bug.cgi?id=925103