Issue #8713: Support alternative start methods in multiprocessing on Unix.
See http://hg.python.org/sandbox/sbt#spawn
diff --git a/Modules/_multiprocessing/multiprocessing.c b/Modules/_multiprocessing/multiprocessing.c
index a4c4b2d..30cb5eb 100644
--- a/Modules/_multiprocessing/multiprocessing.c
+++ b/Modules/_multiprocessing/multiprocessing.c
@@ -126,6 +126,7 @@
{"recv", multiprocessing_recv, METH_VARARGS, ""},
{"send", multiprocessing_send, METH_VARARGS, ""},
#endif
+ {"sem_unlink", _PyMp_sem_unlink, METH_VARARGS, ""},
{NULL}
};