* Makefile.in (build_tooldir): new variable, same as old
	$(tooldir), but without depending on $(libdir)/$(unlibsubdir)
	(GCC_FOR_TARGET): add -B$(build_tooldir)/bin/
	(bootstrap, bootstrap2, bootstrap3, bootstrap4): ditto
	* configure.in (gxx_include_dir): set default based on unlibsubdir
	* Makefile.in (tooldir): ditto
	(cccp.o, cpplib.o): use unlibsubdir implicitly through
	gxx_include_dir, includedir and tooldir
	(protoize.o, unprotoize.o): ditto

From-SVN: r23017