1 files changed, 8 insertions, 3 deletions

diff --git a/gl/m4/lock.m4 b/gl/m4/lock.m4
index aae1701a..d68c12d0 100644
--- a/gl/m4/lock.m4
+++ b/gl/m4/lock.m4
@@ -1,5 +1,5 @@
-# lock.m4 serial 13 (gettext-0.18.2)
-dnl Copyright (C) 2005-2013 Free Software Foundation, Inc.
+# lock.m4 serial 14
+dnl Copyright (C) 2005-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -12,11 +12,16 @@ AC_DEFUN([gl_LOCK],
   if test "$gl_threads_api" = posix; then
     # OSF/1 4.0 and Mac OS X 10.1 lack the pthread_rwlock_t type and the
     # pthread_rwlock_* functions.
+    has_rwlock=false
     AC_CHECK_TYPE([pthread_rwlock_t],
-      [AC_DEFINE([HAVE_PTHREAD_RWLOCK], [1],
+      [has_rwlock=true
+       AC_DEFINE([HAVE_PTHREAD_RWLOCK], [1],
          [Define if the POSIX multithreading library has read/write locks.])],
       [],
       [#include <pthread.h>])
+    if $has_rwlock; then
+      gl_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER
+    fi
     # glibc defines PTHREAD_MUTEX_RECURSIVE as enum, not as a macro.
     AC_COMPILE_IFELSE([
       AC_LANG_PROGRAM(