* configure.in: When checking for X windows, search for an X11

* configure.in: When checking for X windows, search for an X11
	subdirectory of ${x_includes}.

	* configure.in: Check for gettimeofday function, for getdate.y.

        Change `configure' to a mixture of custom code and autoconf stuff.
	autoconf can't derive all the information we need, but we'd really
	like to be able to take advantage of some of its tests, and its
	file-editing facilities.
	* configure.in: Renamed from configure.
	Quote the sections of shell script we want copied literally to
	the configure script.
	(compile): Initialize this to make the autoconf macros' code happy.
	Use AC_PROG_CC, AC_CONST, and AC_RETSIGTYPE instead of writing out
	code to do their jobs.
	Use autoconf to produce Makefile and src/config.h.
	Remove the Makefile-style comment that autoconf places at the top
	of src/config.h.
	(config_h_opts): Removed - no longer necessary.
	* Makefile.in (configname): Renamed to configuration.
	(CONFIG_CFLAGS): Renamed to DEFS.
	(CC, DEFS, C_SWITCH_SYSTEM, version, configuration): Adjusted to
	get values via autoload @cookies@.
	(libsrc_libs): Get this from autoconf.  We used to do nothing
	about this.
	(${SUBDIR}): Pass DEFS to submakes instead of CONFIG_CFLAGS.