diff --git a/src/include/pthread.h b/src/include/pthread.h
index f2a4dff1..937fef36 100644
--- a/src/include/pthread.h
+++ b/src/include/pthread.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pthread.h,v 1.1 2017/10/15 23:40:33 guenther Exp $	*/
+/*	$OpenBSD: pthread.h,v 1.2 2017/10/28 21:23:14 guenther Exp $	*/
 
 /*
  * Copyright (c) 1993, 1994 by Chris Provenzano, proven@mit.edu
@@ -179,10 +179,41 @@ enum pthread_mutextype {
 #define PTHREAD_MUTEX_STRICT_NP		PTHREAD_MUTEX_STRICT_NP
 #define PTHREAD_MUTEX_DEFAULT		PTHREAD_MUTEX_STRICT_NP
 
+/*
+ * On-stack structure for the pthread_cleanup_{push,pop} macros
+ * The actual values are xor'ed with random cookies.
+ */
+struct __thread_cleanup {
+	__uintptr_t __tc_magic;
+	__uintptr_t __tc_next;
+	__uintptr_t __tc_fn;
+	__uintptr_t __tc_arg;
+};
+
+/*
+ * These macro must be used in pairs in the same scope, such that
+ * pthread_cleanup_push() can start a block declaring a variable and
+ * pthread_cleanup_pop() closes that same block.  Any other usage
+ * violates the requirements of the POSIX and Single UNIX standards.
+ */
+#define	pthread_cleanup_push(cb, arg)					\
+	{	/* MATCHED BY CLOSE BRACKET IN pthread_cleanup_pop() */	\
+		struct __thread_cleanup __tc;				\
+		_thread_cleanup_push(cb, arg, &__tc);
+
+#define	pthread_cleanup_pop(execute)					\
+		_thread_cleanup_pop(execute, &__tc);			\
+	}	/* MATCHED BY OPEN BRACKET IN pthread_cleanup_push() */
+
+
+
 /*
  * Thread function prototype definitions:
  */
 __BEGIN_DECLS
+void		_thread_cleanup_pop(int _execute, struct __thread_cleanup *_tc);
+void		_thread_cleanup_push(void (*_fn)(void *), void *_arg,
+		    struct __thread_cleanup *_tc);
 int		pthread_atfork(void (*)(void), void (*)(void), void (*)(void));
 int		pthread_attr_destroy(pthread_attr_t *);
 int		pthread_attr_getstack(const pthread_attr_t *,
@@ -197,8 +228,6 @@ int		pthread_attr_setstack(pthread_attr_t *, void *, size_t);
 int		pthread_attr_setstackaddr(pthread_attr_t *, void *);
 int		pthread_attr_setguardsize(pthread_attr_t *, size_t);
 int		pthread_attr_setdetachstate(pthread_attr_t *, int);
-void		pthread_cleanup_pop(int);
-void		pthread_cleanup_push(void (*) (void *), void *routine_arg);
 int		pthread_condattr_destroy(pthread_condattr_t *);
 int		pthread_condattr_init(pthread_condattr_t *);