This reverts commit b558ff04.
This reverts commit 4a11f206.

The initial import commit failed to retain local changes made to
readline's configure.in (and the commit message erroneously stated that
there were no local changes that needed to be reapplied).  Also the
import caused a couple of build errors and a scattering of testsuite
regressions throughout many arches.  It's probably better to start over
with this import, hopefully more carefully next time.