--- Python-3.9.1/Modules/mmapmodule.c.orig	2021-01-08 00:47:51.535788215 +0000
+++ Python-3.9.1/Modules/mmapmodule.c	2021-01-08 00:48:28.811370361 +0000
@@ -784,7 +784,7 @@
         length = self->size - start;
     }
 
-    if (madvise(self->data + start, length, option) != 0) {
+    if (posix_madvise(self->data + start, length, option) != 0) {
         PyErr_SetFromErrno(PyExc_OSError);
         return NULL;
     }