https://gcc.gnu.org/ml/gcc-patches/2019-09/msg00904.html
	* cp-tree.h (DECL_CLONED_FUNCTION_P): Reimplement using
	IDENTIFIER_CDTOR_P, correct documentation.
	(DECL_CLONED_FUNCTION): Directly access field.
	(decl_cloned_function_p): Delete.
	* class.c (decl_cloned_function_p): Delete.
	* pt.c (instantiate_template_1): Check DECL_CHAIN is a decl.

From-SVN: r275727