PR other/46202: implement install-strip.

PR other/46202: implement install-strip.

/:
	PR other/46202
	* configure.ac: Fix just-built in-tree STRIP name to be
	binutils/strip-new.
	* configure: Regenerate.
	* Makefile.def (install-strip-gcc, install-strip-binutils)
	(install-strip-opcodes, install-strip-ld, install-strip-itcl)
	(install-strip-sid): Mirror dependencies on non-strip variants
	of these targets on the respective -strip prerequisites.
	* Makefile.tpl (install-strip, install-strip-host)
	(install-strip-target): New targets.
	(install-strip-[+module+], install-strip-target-[+module+]):
	New targets.
	* Makefile.in: Regenerate.

etc/:
	* Makefile.in (install-strip): New target.

libiberty/:
	PR other/46202
	* Makefile.in (install-strip): New phony target.
	(install): Also mark as phony.