configury: bump release version to 5.

* configure.ac (AC_INIT): Bump release version to 5.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
bootstrap: sync with upstream.

* bootstrap: Sync with upstream, to fix a bug that still clones
gnulib into the build tree even when gnulib_tool=true is set by
bootstrap.conf.
* gnulib: Not used.  Remove.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>