--- a/m4/ChangeLog
+++ b/m4/ChangeLog
@@ -4,6 +4,12 @@
 	(gl_LOCK_BODY): Remove gl_PREREQ_LOCK invocation.
 	(gl_LOCK): New macro.
 
+2006-08-18  Bruno Haible  <bruno@clisp.org>
+
+	* lock.m4 (gl_LOCK_BODY): Change the default value of gl_use_threads
+	on OSF/1 to no.
+	Reported by Stephen Cartwright <sgcartwr@ucalgary.ca>.
+
 2006-08-22  Eric Blake  <ebb9@byu.net>
 
 	* stdint_h.m4 (gl_AC_HEADER_STDINT_H): Avoid compiler warning.

--- a/m4/lock.m4
+++ b/m4/lock.m4
@@ -1,4 +1,4 @@
-# lock.m4 serial 3 (gettext-0.15.1)
+# lock.m4 serial 4 (gettext-0.15.1)
 dnl Copyright (C) 2005-2006 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -40,7 +40,15 @@
   AC_ARG_ENABLE(threads,
 AC_HELP_STRING([--enable-threads={posix|solaris|pth|win32}], [specify multithreading API])
 AC_HELP_STRING([--disable-threads], [build without multithread safety]),
-    gl_use_threads=$enableval, gl_use_threads=yes)
+    [gl_use_threads=$enableval],
+    [case "$host_os" in
+       dnl Disable multithreading by default on OSF/1, because it interferes
+       dnl with fork()/exec(): When msgexec is linked with -lpthread, its child
+       dnl process gets an endless segmentation fault inside execvp().
+       osf*) gl_use_threads=no ;;
+       *)    gl_use_threads=yes ;;
+     esac
+    ])
   gl_threads_api=none
   LIBTHREAD=
   LTLIBTHREAD=