diff --git a/configure.ac b/configure.ac
index f75c0a98820..f56717f16a4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -4129,26 +4129,28 @@ case $with_file_notification,$NOTIFY_OBJ in
     fi ;;
 esac
 
-dnl kqueue is available on BSD-like systems.
-case $with_file_notification,$NOTIFY_OBJ in
-  kqueue,* | yes,)
-    EMACS_CHECK_MODULES([KQUEUE], [libkqueue])
-    if test "$HAVE_KQUEUE" = "yes"; then
-       AC_DEFINE([HAVE_KQUEUE], [1], [Define to 1 to use kqueue.])
-       CPPFLAGS="$CPPFLAGS -I/usr/include/kqueue"
-       NOTIFY_CFLAGS=$KQUEUE_CFLAGS
-       NOTIFY_LIBS=$KQUEUE_LIBS
-       NOTIFY_OBJ=kqueue.o
-       NOTIFY_SUMMARY="yes -lkqueue"
-    else
-       AC_SEARCH_LIBS([kqueue], [])
-       if test "$ac_cv_search_kqueue" != no; then
-	 AC_DEFINE([HAVE_KQUEUE], [1], [Define to 1 to use kqueue.])
-	 NOTIFY_OBJ=kqueue.o
-	 NOTIFY_SUMMARY="yes (kqueue)"
-       fi
-    fi ;;
-esac
+AS_IF([test "$opsys" != "haiku"], [
+ dnl kqueue is available on BSD-like systems and Haiku, but Haiku's
+ dnl implementation cannot monitor filesystem activity.
+ case $with_file_notification,$NOTIFY_OBJ in
+   kqueue,* | yes,)
+     EMACS_CHECK_MODULES([KQUEUE], [libkqueue])
+     if test "$HAVE_KQUEUE" = "yes"; then
+	AC_DEFINE([HAVE_KQUEUE], [1], [Define to 1 to use kqueue.])
+	CPPFLAGS="$CPPFLAGS -I/usr/include/kqueue"
+	NOTIFY_CFLAGS=$KQUEUE_CFLAGS
+	NOTIFY_LIBS=$KQUEUE_LIBS
+	NOTIFY_OBJ=kqueue.o
+	NOTIFY_SUMMARY="yes -lkqueue"
+     else
+	AC_SEARCH_LIBS([kqueue], [])
+	if test "$ac_cv_search_kqueue" != no; then
+	  AC_DEFINE([HAVE_KQUEUE], [1], [Define to 1 to use kqueue.])
+	  NOTIFY_OBJ=kqueue.o
+	  NOTIFY_SUMMARY="yes (kqueue)"
+	fi
+     fi ;;
+ esac])
 
 dnl g_file_monitor exists since glib 2.18.  G_FILE_MONITOR_EVENT_MOVED
 dnl has been added in glib 2.24.  It has been tested under
diff --git a/src/kqueue.c b/src/kqueue.c
index 4693e130208..aabaab6c8c3 100644
--- a/src/kqueue.c
+++ b/src/kqueue.c
@@ -444,23 +444,29 @@ only when the upper directory of the renamed file is watched.  */)
   if (! NILP (Fmember (Qrevoke, flags))) fflags |= NOTE_REVOKE;
 
   /* Register event.  */
-  EV_SET (&kev, fd, EVFILT_VNODE, EV_ADD | EV_ENABLE | EV_CLEAR,
+  EV_SET (&kev, fd, EVFILT_VNODE, (EV_ADD
+#ifdef EV_ENABLE
+				   | EV_ENABLE
+#endif /* EV_ENABLE */
+				   | EV_CLEAR),
 	  fflags, 0, NULL);
 
-  if (kevent (kqueuefd, &kev, 1, NULL, 0, NULL) < 0) {
-    emacs_close (fd);
-    report_file_error ("Cannot watch file", file);
-  }
+  if (kevent (kqueuefd, &kev, 1, NULL, 0, NULL) < 0)
+    {
+      emacs_close (fd);
+      report_file_error ("Cannot watch file", file);
+    }
 
   /* Store watch object in watch list.  */
   Lisp_Object watch_descriptor = make_fixnum (fd);
   if (NILP (Ffile_directory_p (file)))
     watch_object = list4 (watch_descriptor, file, flags, callback);
-  else {
-    dir_list = directory_files_internal (file, Qnil, Qnil, Qnil, true, Qnil,
-                                         Qnil);
-    watch_object = list5 (watch_descriptor, file, flags, callback, dir_list);
-  }
+  else
+    {
+      dir_list = directory_files_internal (file, Qnil, Qnil, Qnil, true, Qnil,
+					   Qnil);
+      watch_object = list5 (watch_descriptor, file, flags, callback, dir_list);
+    }
   watch_list = Fcons (watch_object, watch_list);
 
   return watch_descriptor;
@@ -486,11 +492,12 @@ WATCH-DESCRIPTOR should be an object returned by `kqueue-add-watch'.  */)
   /* Remove watch descriptor from watch list.  */
   watch_list = Fdelq (watch_object, watch_list);
 
-  if (NILP (watch_list) && (kqueuefd >= 0)) {
-    delete_read_fd (kqueuefd);
-    emacs_close (kqueuefd);
-    kqueuefd = -1;
-  }
+  if (NILP (watch_list) && (kqueuefd >= 0))
+    {
+      delete_read_fd (kqueuefd);
+      emacs_close (kqueuefd);
+      kqueuefd = -1;
+    }
 
   return Qt;
 }