=for apidoc AmU||Nullcv
Null CV pointer.
+(deprecated - use C<(CV *)NULL> instead)
+
=head1 CV Manipulation Functions
=for apidoc Am|HV*|CvSTASH|CV* cv
=cut
*/
-#define Nullcv Null(CV*)
+#ifndef PERL_CORE
+# define Nullcv Null(CV*)
+#endif
#define CvSTASH(sv) ((XPVCV*)SvANY(sv))->xcv_stash
#define CvSTART(sv) ((XPVCV*)SvANY(sv))->xcv_start_u.xcv_start