Andy Dustman: add GNU pth user-space thread support.
diff --git a/Python/thread.c b/Python/thread.c
index fcaa10d..d5e026d 100644
--- a/Python/thread.c
+++ b/Python/thread.c
@@ -150,9 +150,13 @@
 #include "thread_lwp.h"
 #endif
 
+#ifdef _GNU_PTH
+#include "thread_pth.h"
+#else
 #ifdef _POSIX_THREADS
 #include "thread_pthread.h"
 #endif
+#endif
 
 #ifdef C_THREADS
 #include "thread_cthread.h"