* go-gcc.cc (Gcc_backend::type_size): Return 0 for
	void_type_node.
	(Gcc_backend::convert_expression): Don't convert if the type of
	expr_tree is void_type_node.
	(Gcc_backend::array_index_expression): Don't index if the type of
	the array expression is void_type_node.
	(Gcc_backend::init_statement): Don't initialize if the type of the
	initializer expression is void_type_node.
	(Gcc_backend::assignment_statement): Don't assign if the type of
	either the left or right hand side is void_type_node.
	(Gcc_backend::temporary_variable): Don't initialize if the type of
	the initializer expression is void_type_node.

From-SVN: r257334