diff --git a/src/lib/libcrypto/arc4random/arc4random_linux.h b/src/lib/libcrypto/arc4random/arc4random_linux.h
index 992ee6bb..29dad3b9 100644
--- a/src/lib/libcrypto/arc4random/arc4random_linux.h
+++ b/src/lib/libcrypto/arc4random/arc4random_linux.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: arc4random_linux.h,v 1.4 2014/07/19 13:02:28 bcook Exp $	*/
+/*	$OpenBSD: arc4random_linux.h,v 1.5 2014/07/19 14:34:38 bcook Exp $	*/
 
 /*
  * Copyright (c) 1996, David Mazieres <dm@uun.org>
@@ -22,6 +22,12 @@
  * Stub functions for portability.
  */
 
+#include <pthread.h>
+
+static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER;
+#define _ARC4_LOCK()   pthread_mutex_lock(&arc4random_mtx)
+#define _ARC4_UNLOCK() pthread_mutex_unlock(&arc4random_mtx)
+
 static volatile sig_atomic_t _rs_forked;
 
 static inline void
diff --git a/src/lib/libcrypto/arc4random/arc4random_osx.h b/src/lib/libcrypto/arc4random/arc4random_osx.h
index 27428800..55932bb8 100644
--- a/src/lib/libcrypto/arc4random/arc4random_osx.h
+++ b/src/lib/libcrypto/arc4random/arc4random_osx.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: arc4random_osx.h,v 1.4 2014/07/19 13:02:28 bcook Exp $	*/
+/*	$OpenBSD: arc4random_osx.h,v 1.5 2014/07/19 14:34:38 bcook Exp $	*/
 
 /*
  * Copyright (c) 1996, David Mazieres <dm@uun.org>
@@ -22,6 +22,12 @@
  * Stub functions for portability.
  */
 
+#include <pthread.h>
+
+static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER;
+#define _ARC4_LOCK()   pthread_mutex_lock(&arc4random_mtx)
+#define _ARC4_UNLOCK() pthread_mutex_unlock(&arc4random_mtx)
+
 static volatile sig_atomic_t _rs_forked;
 
 static inline void
diff --git a/src/lib/libcrypto/arc4random/arc4random_solaris.h b/src/lib/libcrypto/arc4random/arc4random_solaris.h
index 128f61e0..e5ebbfb7 100644
--- a/src/lib/libcrypto/arc4random/arc4random_solaris.h
+++ b/src/lib/libcrypto/arc4random/arc4random_solaris.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: arc4random_solaris.h,v 1.4 2014/07/19 13:02:28 bcook Exp $	*/
+/*	$OpenBSD: arc4random_solaris.h,v 1.5 2014/07/19 14:34:38 bcook Exp $	*/
 
 /*
  * Copyright (c) 1996, David Mazieres <dm@uun.org>
@@ -21,6 +21,13 @@
 /*
  * Stub functions for portability.
  */
+
+#include <pthread.h>
+
+static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER;
+#define _ARC4_LOCK()   pthread_mutex_lock(&arc4random_mtx)
+#define _ARC4_UNLOCK() pthread_mutex_unlock(&arc4random_mtx)
+
 static volatile sig_atomic_t _rs_forked;
 
 static inline void
diff --git a/src/lib/libcrypto/crypto/arc4random_linux.h b/src/lib/libcrypto/crypto/arc4random_linux.h
index 992ee6bb..29dad3b9 100644
--- a/src/lib/libcrypto/crypto/arc4random_linux.h
+++ b/src/lib/libcrypto/crypto/arc4random_linux.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: arc4random_linux.h,v 1.4 2014/07/19 13:02:28 bcook Exp $	*/
+/*	$OpenBSD: arc4random_linux.h,v 1.5 2014/07/19 14:34:38 bcook Exp $	*/
 
 /*
  * Copyright (c) 1996, David Mazieres <dm@uun.org>
@@ -22,6 +22,12 @@
  * Stub functions for portability.
  */
 
+#include <pthread.h>
+
+static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER;
+#define _ARC4_LOCK()   pthread_mutex_lock(&arc4random_mtx)
+#define _ARC4_UNLOCK() pthread_mutex_unlock(&arc4random_mtx)
+
 static volatile sig_atomic_t _rs_forked;
 
 static inline void
diff --git a/src/lib/libcrypto/crypto/arc4random_osx.h b/src/lib/libcrypto/crypto/arc4random_osx.h
index 27428800..55932bb8 100644
--- a/src/lib/libcrypto/crypto/arc4random_osx.h
+++ b/src/lib/libcrypto/crypto/arc4random_osx.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: arc4random_osx.h,v 1.4 2014/07/19 13:02:28 bcook Exp $	*/
+/*	$OpenBSD: arc4random_osx.h,v 1.5 2014/07/19 14:34:38 bcook Exp $	*/
 
 /*
  * Copyright (c) 1996, David Mazieres <dm@uun.org>
@@ -22,6 +22,12 @@
  * Stub functions for portability.
  */
 
+#include <pthread.h>
+
+static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER;
+#define _ARC4_LOCK()   pthread_mutex_lock(&arc4random_mtx)
+#define _ARC4_UNLOCK() pthread_mutex_unlock(&arc4random_mtx)
+
 static volatile sig_atomic_t _rs_forked;
 
 static inline void
diff --git a/src/lib/libcrypto/crypto/arc4random_solaris.h b/src/lib/libcrypto/crypto/arc4random_solaris.h
index 128f61e0..e5ebbfb7 100644
--- a/src/lib/libcrypto/crypto/arc4random_solaris.h
+++ b/src/lib/libcrypto/crypto/arc4random_solaris.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: arc4random_solaris.h,v 1.4 2014/07/19 13:02:28 bcook Exp $	*/
+/*	$OpenBSD: arc4random_solaris.h,v 1.5 2014/07/19 14:34:38 bcook Exp $	*/
 
 /*
  * Copyright (c) 1996, David Mazieres <dm@uun.org>
@@ -21,6 +21,13 @@
 /*
  * Stub functions for portability.
  */
+
+#include <pthread.h>
+
+static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER;
+#define _ARC4_LOCK()   pthread_mutex_lock(&arc4random_mtx)
+#define _ARC4_UNLOCK() pthread_mutex_unlock(&arc4random_mtx)
+
 static volatile sig_atomic_t _rs_forked;
 
 static inline void