diff --git a/src/pyfastani/_patch.pxi b/src/pyfastani/_patch.pxi
index a79afbc..0a41220 100644
--- a/src/pyfastani/_patch.pxi
+++ b/src/pyfastani/_patch.pxi
@@ -1,6 +1,6 @@
 cdef extern from *:
     """
-    #ifndef HAS_PYINTERPRETERSTATE_GETID
+    #ifndef HAVE_PYINTERPRETERSTATE_GETID
     int64_t PyInterpreterState_GetID(PyInterpreterState *interp) {
         return 0;
     }