[MacPorts] #60737: gdal-grass: Update to 3.1.1

[MacPorts]

#60737: gdal-grass: Update to 3.1.1
-------------------------+----------------------
  Reporter:  ryandesign  |      Owner:  Veence
      Type:  update      |     Status:  assigned
  Priority:  Normal      |  Milestone:
 Component:  ports       |    Version:
Resolution:              |   Keywords:
      Port:  gdal-grass  |
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Comment (by ryandesign):

 The convenience of subports is that as many lines of a portfile as you
 want can be shared amongst multiple ports. This helps reduce code
 duplication and helps prevent errors from creeping in when a developer
 makes a change to one file without realizing that they should make the
 same change in other files. In the case of gdal and gdal-grass you'd be
 sharing the version and livecheck at least, and just having both ports in
 the same file would probably lead to remembering to update them both at
 once. But if the ports don't otherwise have many lines in common, maybe
 subports aren't the right choice.

 Subports are great when there are several ports that you want to create
 out of a single distfile because then you're sharing the distname and
 checksums too. Examples are [browser:macports-
 ports/graphics/netpbm/Portfile netpbm] (libnetpbm subport), [browser
 :macports-ports/lang/llvm-9.0/Portfile llvm-9.0] (clang-9.0 and lldb-9.0
 subports), and [browser:macports-ports/graphics/graphviz/Portfile
 graphviz] (graphviz-gui and gvedit subports). But with gdal-grass, which
 has a different distfile from gdal, you'd still have to remember to update
 the subport's checksums. An example of that is [browser:macports-
 ports/graphics/synfig/Portfile synfig] (synfigstudio and ETL subports).
 Using subports can also ironically make the portfile more complex, since
 you have to wrap some parts of it in an `if {${subport} eq ${name}} {...}`
 block.

 So using a subport is not necessarily the best choice, I just wanted to
 point it out as an option. Just adding a comment at the top of related
 ports advising people to keep them updated together is also a perfectly
 viable option; I use that for example in [browser:macports-
 ports/graphics/ImageMagick/Portfile ImageMagick] and [browser:macports-
 ports/perl/p5-perlmagick/Portfile p5-perlmagick], or [browser:macports-
 ports/sysutils/libvirt/Portfile libvirt] and [browser:macports-
 ports/python/py-libvirt/Portfile py-libvirt].

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Ticket URL: <https://trac.macports.org/ticket/60737#comment:2>
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