type_traits: Implemenet is_polymorphic.

type_traits: Implemenet is_polymorphic.

2005-03-03  Paolo Carlini  <pcarlini@suse.de>

	* include/tr1/type_traits: Implemenet is_polymorphic.
	(is_empty): Minor tweaks.
	* testsuite/testsuite_tr1.h: Add test types.
	* testsuite/tr1/4_metaprogramming/type_properties/
	is_polymorphic/is_polymorphic.cc: New.
	* testsuite/tr1/4_metaprogramming/type_properties/
	is_polymorphic/typedefs.cc: Likewise.
	* testsuite/tr1/4_metaprogramming/composite_type_traits/
	is_union_or_class/is_union_or_class.cc: Add tests.

From-SVN: r95829