GTK3 on Darwin

[Andrea Giammarchi <andrea giammarchi gmail com>]

I'm playing around with GTK3 +quartz and WebKit2GTK + quartz on Darwin

( https://github.com/WebReflection/jsgtk-twitter )

Overall everything looks fine and consistent but there are a couple of very basic functionalities that are apparently not supported and make the app sort of unusable.

org.freedesktop.Notifications throws errors with very basic code like the following one:

```js

notify(notifications, messages) {

  if (this.info.showNotification) {

    if (!Notify.isInitted())

      Notify.init(this.title);

    new Notify.Notification({

      summary: `You have ${notifications + messages} updates`,

      body: (

        (notifications ? `${notifications} notifications` : '') +

        (messages ?

          ((notifications ? ' and ' : '') + `${messages} messages`) : '')

      ),

      iconName: this.icon

    }).show();

  }

}

```

but it works without a glitch on any Linux distro I could try.

Screenshot example here:

https://twitter.com/WebReflection/status/728497893968105472

There is also a very simple Gio call like

```js

open(uri) {

  Gio.AppInfo.launchDefaultForUri(uri, null);

}

```

which fails on Darwin only every single time saying `Operation not permitted`

It supposed to open the default browser outside the app and, loading the provided url.

Since being able to notify and open a default app looks like very common Desktop App helpers, it surprised me I have errors here, for an otherwise pleasant and straight forward experience in GTK quartz.

As summary: can anyone please confirm development on Darwin is still active and, eventually, if it's me doing something wrong through these basic snippets?

The syntax is ES2016 via jsgtk which is a GJS wrapper but basically all it does is making ruby_cased GJS camelCase and transpile via Babel upfront modules once and on demand before using them, if you'd like a GJS clean example I can write one for you.

The second case would basically be:

```gjs

var uri = 'https://google.com/';

imports.gi.Gio.AppInfo.launch_default_for_uri(uri, null);

```

Thank you in advance for any kind of help/clarification.

Best Regards.