BACKWARDS Compatibility between libgambit [4.9.3] and libgambc [4.7.9]

[mgorges]

When back-porting WHEN and UNLESS I noticed a subtle difference between gambc and gambit. Over all gambit ought to be an improvement over gambc. Iff - that is - we knew no collateral damage to expect.

Is there any issue actually known, which blocks a move from gambc to gambit?

Before diving deeper into profiling/optimizing these things, I'd like to back-port/fix these things. So far I know of only a single such subtle difference wrt. optional arguments. If there was nothing else, I'd rather ignore gambc compatibility.

Originally posted by @0-8-15 in #341 (comment)

[mgorges]

There is a relevant discussion in the Gambit mailing list, starting at https://mailman.iro.umontreal.ca/pipermail/gambit-list/2016-June/008295.html - note this discussion continues into July at https://mailman.iro.umontreal.ca/pipermail/gambit-list/2016-July/008310.html and beyond. It spoke directly to the request for a long-term supported version of 4.7.2 as this is before a major change in development direction of gambit, which focused more on adding additional output languages rather than performance and stability with only a limited (C) target.

[mgorges]

In the end this come down to risk tolerance and developer time commitment. For our safety-critical medical device developments we actually use an even older version of Gambit, for which we forked LambdaNative to stay at 4.7.0 as there were problems between it and 4.7.3 that took us a full month to debug and in the end a revert was the best way forward. We also started building this in a virtual machine with fixed other libraries.

Personally, I have been running first 4.8.5 for about 2 years, and 4.9.3 for about 1.5 years to make desktop apps and mobile apps. However, I still have an embedded Linux system, that serves vital signs data to other devices, for which I build against 4.7.3. I believe the rest of our small internal team uses 4.7.3 exclusively, and ran VERY large studies (read many 10,000s of users) using Android devices with it.

[gambiteer]

I could help to some extent. I'd probably have to learn how to run code on simulated devices.