add threaddata

src/libthread/thread.c

@@ -327,6 +327,12 @@ procdata(void)
 	return &proc()->udata;
 }
 
+void**
+threaddata(void)
+{
+	return &proc()->thread->udata;
+}
+
 extern Jmp *(*_notejmpbuf)(void);
 static Jmp*
 threadnotejmp(void)

src/libthread/threadimpl.h

@@ -70,6 +70,7 @@ struct _Thread
 	Proc	*proc;
 	char	name[256];
 	char	state[256];
+	void *udata;
 };
 
 struct _Procrendez