type_traits (add_reference): Robustify vs reference to void.

type_traits (add_reference): Robustify vs reference to void.

2006-09-22  Paolo Carlini  <pcarlini@suse.de>

	* include/tr1/type_traits (add_reference): Robustify vs
	reference to void.
	* testsuite/tr1/4_metaprogramming/reference_modifications/
	add_reference.cc: Add test.

	* include/tr1/memory: include <tr1/type_traits>.
	* include/tr1/boost_shared_ptr.h (__shared_ptr<>::operator*):
	Use add_reference instead.
	* testsuite/tr1/2_general_utilities/memory/enable_shared_from_this/
	explicit_instantiation/1.cc: New.
	* testsuite/tr1/2_general_utilities/memory/shared_ptr/
	explicit_instantiation/1.cc: Likewise.
	* testsuite/tr1/2_general_utilities/memory/weak_ptr/
	explicit_instantiation/1.cc: Likewise.

	* testsuite/util/testsuite_tr1.h: Tweak; avoid empty enum.

	* include/tr1/type_traits_fwd.h: Spelling fix.

	* include/tr1/boost_shared_ptr.h: Obvious stylistic fixes.

From-SVN: r117147