* configure.ac: Quote strings throughout in good Autoconf style.

	* configure.ac: Quote strings throughout in good Autoconf style.
	Remove AC_PROG_YACC invocation. Search for docbook2dvi, et al and
	expect using AC_PATH_PROG. Remove DJ_AC_PATH_DOCBOOK in favour of
	existing macros. Remove stale BOARDS and CONFIG substs. Ensure Tcl
	is at version 8.3 or greater.
	* configure: Regenerate.
	* acinclude.m4: Remove.
	* aclocal.m4: Regenerate.
	* Makefile.in: Likewise.
	* doc/Makefile.am (%.pdf: %.sgml): Use $(DOCBOOK2PDF).
	(%.dvi: %.sgml): Use $(DOCBOOK2DVI).
	(%.html: %.sgml): Use $(DOCBOOK2HTML).
	* doc/Makefile.in: Regenerate.
	* example/Makefile.in: Likewise.
	* testsuite/Makefile.in: Likewise.
	* testsuite/libdejagnu/Makefile.in: Likewise.
	* TODO: Update.