include/

include/
	* demangle.h (DEMANGLE_COMPONENT_HIDDEN_ALIAS): New.
libiberty/
	* cp-demangle.c (d_dump): Handle DEMANGLE_COMPONENT_HIDDEN_ALIAS.
	(d_make_comp, d_print_comp): Likewise.
	(d_special_name): Generate one.
	* testsuite/demangle-expected: Add a hidden alias test.