Support arm64 architecture on macOS

[khaeru]

This PR responds to #531.

• Improve .backend.jdbc:

  • Pass -Djava.library.path=… when starting the JVM, giving two directories containing the required binary libraries (with the extension .so on Linux; .dll on Windows; and .dylib on macOS):
  • The …/apifiles/Java/api/ directory within the user's GAMS installation directory.
  • The ixmp/backend/jdbc/ directory within the package itself, which contains (very old) bundled copies of the same files.

  The second directory is redundant if the first one is present (i.e. if a GAMS installation exists). To confirm this, the PR currently deletes the bundled libraries entirely. These commits could also be dropped instead.

• Expand the CI matrix to include both x86_64 and arm64 architectures on the macOS.
  • Use an updated version of iiasa/actions/setup-gams per iiasa/actions#13. This version installs an architecture-appropriate GAMS, and handles caching automatically.
  • Exclude macos-latest (arm64) for Python 3.8 and 3.9, as there are no pre-built wheels for JPype1 for this combination.

How to review

• Read the diff.
• Note the CI checks all pass.
• message_ix usage: Install ixmp from this branch on a macOS arm64 system with an arm64 version of Python. Run the test suite or other code and confirm the code functions as expected.
• Scenario Explorer usage: Consider implications for non-message_ix deployments; particularly, for the Scenario Explorer. Is GAMS installed in these contexts? Will the absence of the .dylib, .so, and/or .dll files bundled with the ixmp Python package affect these deployments?

PR checklist

• [x] Continuous integration checks all ✅
• [x] Add or expand tests; coverage checks both ✅
• ~Add, expand, or update documentation.~
• [x] Update release notes.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 98.7%. Comparing base (f08447f) to head (97d9f30).

:exclamation: Current head 97d9f30 differs from pull request most recent head 1d40c22

Please upload reports for the commit 1d40c22 to get more accurate results.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #532 +/- ## ======================================= - Coverage 98.8% 98.7% -0.1% ======================================= Files 44 44 Lines 4804 4803 -1 ======================================= - Hits 4747 4744 -3 - Misses 57 59 +2 ``` | [Files](https://app.codecov.io/gh/iiasa/ixmp/pull/532?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa) | Coverage Δ | | |---|---|---| | [ixmp/backend/jdbc.py](https://app.codecov.io/gh/iiasa/ixmp/pull/532?src=pr&el=tree&filepath=ixmp%2Fbackend%2Fjdbc.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa#diff-aXhtcC9iYWNrZW5kL2pkYmMucHk=) | `97.2% <100.0%> (-0.2%)` | :arrow_down: | ... and [4 files with indirect coverage changes](https://app.codecov.io/gh/iiasa/ixmp/pull/532/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa)

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 98.8%. Comparing base (cf56d03) to head (caaaa3d). Report is 41 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #532 +/- ## ===================================== Coverage 98.8% 98.8% ===================================== Files 44 44 Lines 4796 4813 +17 ===================================== + Hits 4739 4756 +17 Misses 57 57 ``` | [Files with missing lines](https://app.codecov.io/gh/iiasa/ixmp/pull/532?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa) | Coverage Δ | | |---|---|---| | [ixmp/backend/jdbc.py](https://app.codecov.io/gh/iiasa/ixmp/pull/532?src=pr&el=tree&filepath=ixmp%2Fbackend%2Fjdbc.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa#diff-aXhtcC9iYWNrZW5kL2pkYmMucHk=) | `97.4% <100.0%> (+<0.1%)` | :arrow_up: | | [ixmp/model/gams.py](https://app.codecov.io/gh/iiasa/ixmp/pull/532?src=pr&el=tree&filepath=ixmp%2Fmodel%2Fgams.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=iiasa#diff-aXhtcC9tb2RlbC9nYW1zLnB5) | `96.2% <100.0%> (+0.3%)` | :arrow_up: |

[khaeru]

@glatterf42 let me know whether you think there is urgency to include this in the 3.9 release.

We would need to invite and wait for reviews from:

• Ravit, Sidd, and/or Setu —to check behaviour on their machines.
• Philip or someone else —to address the point about impacts on Scenario Explorer deployments.

Given this might take a few days, and the first three are probably capable to use it from main in the period between the 3.9 and 3.10 releases, I would lean to "no". OTOH, if we have users in the upcoming workshop who have macOS arm64 machines, this might (not necessarily) save some support overhead.

If we wait, then I will also wait until after the workshop to request a review of iiasa/actions#13.

[glatterf42]

I'd also say it's likely not urgent. Workshop users will learn about GitHub anyway and if they need to use this branch, this will be a good opportunity to practice. They could also then provide feedback about their install process. However, I think we can already invite review from our team members and if these come in very soon, we can maybe still include this in 3.9 :)

[khaeru]

@ravitby @SiddharthJoshi-Git @setupelz —could you please try the steps above under "How to review" / "message_ix usage" and let us know the results?

@phackstock —could you please comment on the questions above under "How to review" / "Scenario Explorer usage"?

[khaeru]

Great, thanks for confirming.

[khaeru]

@glatterf42, since the other requested colleagues seem unable to review this over the past ~6 weeks, I propose we merge and wait for feedback that may come as they/others use it from main. If we don't get positive confirmation before we start prep for the next release, then we can ask again.