Partial patch from SF #452266, by Jason Petrone.

This changes Pythread_start_thread() to return the thread ID, or -1
for an error.  (It's technically an incompatible API change, but I
doubt anyone calls it.)
diff --git a/Python/thread_foobar.h b/Python/thread_foobar.h
index 6edd0f9..4baf7e7 100644
--- a/Python/thread_foobar.h
+++ b/Python/thread_foobar.h
@@ -10,7 +10,7 @@
 /*
  * Thread support.
  */
-int
+long
 PyThread_start_new_thread(void (*func)(void *), void *arg)
 {
 	int success = 0;	/* init not needed when SOLARIS_THREADS and */
@@ -19,7 +19,7 @@
 	dprintf(("PyThread_start_new_thread called\n"));
 	if (!initialized)
 		PyThread_init_thread();
-	return success < 0 ? 0 : 1;
+	return success < 0 ? -1 : 0;
 }
 
 long