Add a CMake flag to enable Wasm exceptions in the BinaryenJS build

[dschuff]

This is useful for wasm performance (and for size tests, since Emscripten EH makes the binary unnecessarily slow and large).

[dschuff]

I guess at some point we might want to make this the default, as most wasm runtimes will support exceptions. I imagine this might have already happened with some version of node... do we have any idea which?

[aheejin]

What do you mean by "it" in "it happened with some version of node"? Having Wasm EH support? Or supporting it by default without a flag? I just tested with several versions of node on my local machine and they turn on EH support by default (= without a flag) as of v17.5. v17.0 doesn't turn it on by default.

Not sure what you mean by "make this the default".

[MaxGraey]

Wasm exceptions enabled by default in node 17. Current LTS node is 18 so it absolutely ok enable exceptions by default I guess

See https://webassembly.org/roadmap

[aheejin]

Hmm my local v17.0 was a nightly version I installed a few years back, so it might be the reason it didn't work..? Anyway, thanks for the info!