Suppress warning about unix-sync in nnmaildir.el

* nnmaildir.el (nnmaildir-request-replace-article): Check if the
function `unix-sync' is bound before running it.

1 files changed, 2 insertions, 1 deletions

diff --git a/lisp/gnus/nnmaildir.el b/lisp/gnus/nnmaildir.el
index ac125c905a5..3becee35112 100644
--- a/lisp/gnus/nnmaildir.el
+++ b/lisp/gnus/nnmaildir.el
@@ -1396,7 +1396,8 @@ This variable is set by `nnmaildir-request-article'.")
       (with-current-buffer buffer
         (write-region (point-min) (point-max) tmpfile nil 'no-message nil
                       'excl))
-      (unix-sync) ;; no fsync :(
+      (when (fboundp 'unix-sync)
+        (unix-sync)) ;; no fsync :(
       (rename-file tmpfile (concat (nnmaildir--cur dir) file suffix) 'replace)
       t)))