Note: auto* tools updated

For those of you that rebuild the configure script, please note that the
required auto* tools have been updated. The script now

autoconf 2.60
libtool 1.5.22
automake 1.9.6

The versions we were using were getting a little stale (several years
out of date) and the change was made in an attempt to get better support
from libtool for --whole-archive option (see PR780).