Bug #794140: cygwin builds do not embed

The embed2.diff patch solves the user's problem by exporting the missing
symbols from the Python core so Python can be embedded in another Cygwin
application (well, at lest vim).
diff --git a/Python/marshal.c b/Python/marshal.c
index 5aaa382..0bb7b4f 100644
--- a/Python/marshal.c
+++ b/Python/marshal.c
@@ -875,7 +875,7 @@
 	{NULL,		NULL}		/* sentinel */
 };
 
-void
+PyMODINIT_FUNC
 PyMarshal_Init(void)
 {
 	(void) Py_InitModule("marshal", marshal_methods);