Excise DL_EXPORT/DL_IMPORT from Modules/*. Required adding a prototype

for Py_Main().

Thanks to Kalle Svensson and Skip Montanaro for the patches.

Modules/threadmodule.c

@@ -360,7 +360,7 @@ A lock is not owned by the thread that locked it; another thread may\n\
 unlock it.  A thread attempting to lock a lock that it has already locked\n\
 will block until another thread unlocks it.  Deadlocks may ensue.");
 
-DL_EXPORT(void)
+PyMODINIT_FUNC
 initthread(void)
 {
 	PyObject *m, *d;