re PR c++/16338 (ICE when throwing a compound literal)

re PR c++/16338 (ICE when throwing a compound literal)

	PR c++/16338
	* cp-tree.h (DECL_INTEGRAL_CONSTANT_VAR_P): New macro.
	* call.c (null_ptr_cst_p): Handle variables with constant
	initializers.
	* pt.c (convert_nontype_argument): Use
	DECL_INTEGRAL_CONSTANT_VAR_P.
	* semantics.c (finish_id_expression): Likewise.

	PR c++~/16489
	* decl.c (duplicate_decls): Reject duplicate namespace
	declarations.

	PR c++/16810
	* typeck.c (build_ptrmemfunc): Loosen assertion.

	PR c++/16338
	* g++.dg/init/null1.C: New test.
	* g++.dg/tc1/dr76.C: Adjust error marker.

	PR c++/16489
	* g++.dg/parse/namespace10.C: New test.

	PR c++/16810
	* g++.dg/inherit/ptrmem2.C: New test.

From-SVN: r85421