decl.c (gnat_to_gnu_entity): Simplify the condition under which a constant renaming is treated as a normal...

	* decl.c (gnat_to_gnu_entity) <Object>: Simplify the condition under
	which a constant renaming is treated as a normal object declaration.
	* trans.c (lvalue_required_p) <N_Slice>: New case, extracted from
	the N_Indexed_Component case.
	<N_Indexed_Component>: Fall through to above case.
	<N_Object_Renaming_Declaration>: Return true for all composite types.

From-SVN: r128268