[MacPorts] #64820: xfce, xfce4-session, xfwm4, xfdesktop: Update to 4.16.x

[MacPorts]

#64820: xfce, xfce4-session, xfwm4, xfdesktop: Update to 4.16.x
-------------------------------------------------+----------------------
  Reporter:  syurin-nagatuki                     |      Owner:  (none)
      Type:  update                              |     Status:  assigned
  Priority:  Normal                              |  Milestone:
 Component:  ports                               |    Version:  2.7.2
Resolution:                                      |   Keywords:
      Port:  xfce xfce4-session xfwm4 xfdesktop  |
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Comment (by ryandesign):

 Replying to [comment:7 barracuda156]:
 > I will have to see which other ports are there besides those in `xfce`
 folder itself. It but a few, I could probably do it, since I want to fix
 them for older systems anyway.

 `port echo homepage:'xfce\.org'` is one way to identify them.

 You may want to look back at some of the commits where I updated some of
 the ports to 4.16.x to get an idea of the kinds of changes that were
 needed.

 > Could you just help with livecheck? I assume the code will be identical,
 so if you give me a correct template, I will use it across xfce ports.

 The developers sure aren't making it easy for us. They put each distfile
 into a directory named after the branch. `master_sites` is of course set
 to that directory. Livecheck by default looks in `master_sites`. This
 means we don't notice when a new major branch is released. If the xfce
 ports had a maintainer, that might be sufficient, assuming the maintainer
 has another way of being notified of new major releases, such as by being
 subscribed to the [https://mail.xfce.org/mailman/listinfo/xfce-announce
 xfce-announce mailing list].

 Each xfce project has its own page which lists the latest release number,
 but I checked the [https://docs.xfce.org/xfce/xfconf/start xfconf page] as
 an example and it says the latest release is 4.19.0. Like all xfce version
 numbers where the second number is odd, that's a development version; we
 want the latest stable version number, so checking the project's page
 won't work.

 I see there is a gitlab repository, so using its list of tags is probably
 going to be the way to do it. I'll commit this change to xfconf shortly so
 you can see how that's done.

 Be aware that the gitlab portgroup only supports downloading .tar.bz2
 files. If any xfce port needs to download a non-.tar.bz2 file, then the
 gitlab portgroup probably cannot be used. That's #64960.

-- 
Ticket URL: <https://trac.macports.org/ticket/64820#comment:8>
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