pert:
I think the next step would be to determine the minimum code that will still cause the issue.
I'm willing to try this but it would need to involve a strategic approach rather than going in blind. Otherwise given the size of our project and the randomness of the errors I think one could easily lose vast amounts of time wasted without arriving at any useful conclusions. Even small changes to the code seems to shift the location of reboots, which themselves may not occur for several minutes. I am fortunate right now the location where these occur is very noticeable, but in other places it would not be. Naturally removing portions of code itself breaks the program so those have to be worked out and distinguished from the compiler-specific errors. It all becomes a very big mess quickly.
And I wonder what is to say if the very size of our code base is in fact the problem, rather than the code itself? How many Arduino projects compile to over 100k bytes?
What I would really need are likely culprits to start looking at, or some kind of hunch that might lead me to focus my attention in some place more likely to be problematic. Otherwise I am flailing about blind.
Would it be useful to start a new thread in this forum with a better title related to the compiler? Or perhaps over at avrfreaks.net? From browsing over there in the past my impression has been they don't like Arduino questions but I suppose if it could be shown to be a compiler issue they might not react as badly... I really don't know!