Draft Change: Use Squirrel version 3.0.7

[nikolas]

Here's a branch to play around with that updates OpenTTD's modified
version of Squirrel 2.2.5 to a similarly modified version of
Squirrel 3.0.7.

This is a work-in-progress as the compiler warnings need to be addressed.
But, it's in a usable state to test out AIs and game scripts using
Squirrel 3.

[nielsmh]

Fails on Windows since it compiles with SQUNICODE defined, which defined SQChar as wchar_t and becomes incompatible.

I think this is a high risk change not worth pursuing, it will most likely break a large number of existing AI and GS. In my opinion, if even a single existing addon breaks this can't be merged.

[LordAro]

In my opinion, if even a single existing addon breaks this can't be merged.

Agreed, unless the old behaviour can be restored

I'd like to be annoying and ask that adding squirrel 3 and making modifications to it should be separate commits. Breaks the "every commit should compile" rule, but I think it would be worth it to make it more obvious which are our modifications

[nikolas]

I think this is a high risk change not worth pursuing, it will most likely break a large number of existing AI and GS. In my opinion, if even a single existing addon breaks this can't be merged.

Absolutely this will break AIs that depend on Squirrel 2 features. For example, AdmiralAI breaks because it uses for(local c = 0; c < vargc; c++) {, and vargc is no longer a keyword in Squirrel 3.

I don't intend this to be merged any time soon. Rather, this is an experimental branch for anyone who wants to test things in Squirrel 3.

[nikolas]

I've separated this out into two commits on @LordAro's suggestion. It's easy to see the modifications now. That was a big challenge with updating this in the first place.

[LordAro]

Mm. A fun experiment I think, but I don't see this going any further - not unless you want to reimplement all the "removed" features from Squirrel 2 -> 3 :)

It's possible there are other improvements that could be taken from SQ3, but those need to be rather more selective than this!