diff -Naur Python-3.8.0-orig/Modules/_multiprocessing/multiprocessing.c Python-3.8.0/Modules/_multiprocessing/multiprocessing.c
--- Python-3.8.0-orig/Modules/_multiprocessing/multiprocessing.c	2019-10-14 16:34:47.000000000 +0300
+++ Python-3.8.0/Modules/_multiprocessing/multiprocessing.c	2019-10-22 10:04:35.437120500 +0300
@@ -128,7 +128,7 @@
     {"recv", multiprocessing_recv, METH_VARARGS, ""},
     {"send", multiprocessing_send, METH_VARARGS, ""},
 #endif
-#if !defined(POSIX_SEMAPHORES_NOT_ENABLED) && !defined(__ANDROID__)
+#if defined(MS_WINDOWS) || (!defined(POSIX_SEMAPHORES_NOT_ENABLED) && !defined(__ANDROID__))
     {"sem_unlink", _PyMp_sem_unlink, METH_VARARGS, ""},
 #endif
     {NULL}