Yubico/yubico-c-client — pull request #11 by neverpanic (2013-01-18 13:19:23+00:00)
Title: configure.ac: Call AM_PROG_AR if available

As mentioned in pull request #8, let's use
```autoconf
m4_ifdef([AM_PROG_AR], [AM_PROG_AR])
```

I can confirm this works with automake 1.13 (and probably also 1.12).