demeter: replace ifeffit requirement with xraylarch

[joefowler (Joe Fowler)]

The port:demeter depends on port:ifeffit. The ​latter is deprecated and hasn't been updated in seven years. Meanwhile, the code has seen compiler deprecations and warnings turn into errors. See tickets #63246 #61570, #60340, #59630.

As far as I can tell, outside of the Mac Ports context, demeter relies on either ifeffit or its replacement ​Larch. I've written to demeter's author to make sure that's correct. If so, it makes no sense to fix new problems in unmaintained code. We should simply use Larch instead.

I propose the following solution, which I'm working on:

1. Create a new port py-xraylarch
2. Create new ports py-* for its various dependencies. There seem to be 6 that don't have existing ports (peakutils, pyshortcuts, ​xraydb, ​silx, ​hdf5plugin, pymatgen), but these of course might have their own dependencies.
3. Update port ​py-fabio to use python38 and 39 and latest upstream version. This step is independent, so I already filed it as #63554.
4. Update port demeter to depend on py-xraylarch instead of ifeffit and its Perl wrapper p5-ifeffit
5. Obsolete the ports ifeffit and p5-ifeffit (or replace?)
6. Obsolete the sub-port demeter-devel. (It is no longer actually different from demeter and hasn't been for years.)

[joefowler (Joe Fowler)]

In 1c3b15063c6106ede54996be9d4acfd41d7511ce/macports-ports (master):

py-fabio: update to version 0.12.0

py-fabio: update to version 0.12.0

• update to version 0.12.0
• make subports for Python 3.8 and 3.9.
• make Python 2.7 use older (0.9.0) version of fabio, because 0.12.0 won't build.

Closes: #63554
See #63555