Fix for PR debug/45088

gcc/

	* dwarf2out.c (gen_type_die_with_usage): Do not try to emit debug
	info for a redundant typedef that has DECL_ORIGINAL_TYPE set. Use
	that underlying type instead.

gcc/testsuite/

	* g++.dg/debug/dwarf2/self-ref-1.C: New test.
	* g++.dg/debug/dwarf2/self-ref-2.C: Likewise.

From-SVN: r167976