notifications.macos: Notifications for macOS.

They don't seem to always pop up. I think the delegate needs to be set to respond to a message to always show the notification.

extra/notifications/macos/authors.txt

@@ -0,0 +1 @@
+Doug Coleman

extra/notifications/macos/macos.factor

@@ -0,0 +1,19 @@
+! Copyright (C) 2018 Doug Coleman.
+! See http://factorcode.org/license.txt for BSD license.
+USING: cocoa cocoa.application cocoa.classes kernel locals ;
+IN: notifications.macos
+
+IMPORT: NSUserNotification
+IMPORT: NSUserNotificationCenter
+
+:: make-notification ( title text -- notification )
+    NSUserNotification -> alloc -> init -> autorelease
+    [ title <NSString> -> setTitle: ] keep
+    [ text <NSString> -> setInformativeText: ] keep ;
+
+: send-notification ( title text -- )
+    make-notification
+    [
+        NSUserNotificationCenter -> defaultUserNotificationCenter
+    ] dip
+    -> deliverNotification: ;

extra/notifications/macos/platforms.txt

@@ -0,0 +1 @@
+macosx