Use autoconf variables for preview version and date.

* .gitignore: Ignore preview/preview.el.

* Makefile.in (DISTCLEANFILES): Add preview/preview.el.
(release-commit): Write new version announcement also into
preview/ChangeLog.

* aclocal.m4: Add a third argument to
`AC_DATE_VERSION_FROM_CHANGELOG' specifying the ChangeLog file.

* configure.ac: Use new third argument of
`AC_DATE_VERSION_FROM_CHANGELOG'.  Retrieve preview date and
version from its ChangeLog.  Add preview/preview.el to output
files.

* preview/preview.el.in: Rename from "preview/preview.el".
(preview-version): Use @PREVIEWVERSION@ autoconf variable.
(preview-release-date): Use @PREVIEWDATE@ autoconf variable.
(preview-report-bug): Adapt to new `preview-version' format.
Manually adjust preview release version in dtx.

* preview/latex/preview.dtx: Manually change the release version.
Fix in LaTeX-largest-level-set for XEmacs compatibility.

* latex.el (LaTeX-largest-level-set): Set `outline-heading-alist'
only if it is bound.
Fix indentation of tabularx environment closing.

* latex.el (LaTeX-indent-environment-list): Remove setter
lambda.
(LaTeX--tabular-like-end): Remove variable.
(LaTeX-indent-tabular): Move setter function from
LaTeX-indent-environment-list to generate tabular-end regex when
called.

Signed-off-by: Mosè Giordano <mose@gnu.org>
Minor fix to previous change.

Signed-off-by: Mosè Giordano <mose@gnu.org>
Release_11.88
Create a top level directory in the preview tarball.

* Makefile.in (CTANDIR): New variable.
(preview-ball): Create a top level directory "preview/" in the
preview tarball, as required by CTAN.  Save the tarball to
$(CTANDIR) instead of $(FTPDIR).