-#if defined(MULTIPLICITY) || defined(PERL_IMPLICIT_CONTEXT)
-# define VMG_MULTIPLICITY 1
-# ifndef tTHX
-# define tTHX PerlInterpreter*
+#ifndef VMG_MULTIPLICITY
+# if defined(MULTIPLICITY) || defined(PERL_IMPLICIT_CONTEXT)
+# define VMG_MULTIPLICITY 1
+# else
+# define VMG_MULTIPLICITY 0