0.pre7.46:

	various refactorings and tidying..
	..redid the hairy remove-ourselves-from-tail-set mess in
		MERGE-LETS as a separate function,
		DEPART-FROM-TAIL-SET
	..split diagnostic/reporting stuff (starting around
		(DECLAIM (SPECIAL *CURRENT-PATH*)) out of ir1util.lisp
		into ir1report.lisp
	..moved UNIX-HOST stuff around in an effort to get rid
		of compiler not-defined-(yet) warnings
	..split target-pathname.lisp out of pathname.lisp to support
		this
	..moved target-only HOST stuff from pathname.lisp (which is
		built both on host and target) to filesys.lisp (which
		is flagged as :NOT-HOST in stems-and-flags.lisp-expr)
	..Since there's no longer any numbers.lisp or
		host-numbers.lisp to contrast to, target-numbers.lisp
		really ought to be called numbers.lisp.
	..split ir1-translators.lisp out of ir1tran.lisp (as per FIXME)
	..moved IDENTITY, COMPLEMENT, and CONSTANTLY out of list.lisp
		into funutils.lisp