Wasm fn feature gate

[zrzka]

Problem

• cdsl have a function generate_ui
• if reconfix does use cdsl as a dependency, this generate_ui fn is in the reconfix bindings as well, which is something I do not want
• if I define generate_ui in the reconfix, it doesn't compile, because linker complaints about two functions with the same name

In other words. If cdsl is used to generate balena-cdsl NPM package, it's good as it is now. But if you'd like to use cdsl as a dependency and you do not want to have cdsl JS bindings in your NPM package (like reconfix), there's no way.

What this PR does

• adds feature disable-wasm-bindings
• wasm.rs is gated with target arch wasm32 & not(feature = "disable-wasm-bindings"))

By default, nothing changes. But for the reconfix I can say something like - I'd like to use cdsl, but without cdsl JS bindings.

Feature name

Initially, I was thinking about a feature called npm-package and build scripts update. I have found that wasm-pack build does support -- --features "npm-package" (added to 0.6). Unfortunately, wasm-pack test doesn't. Thus it must be enabled by default and we have to introduce disabling feature. Then the disable-wasm-bindings it is.

[zrzka]

I'll add this to temen as well once we agree on a way how to do it.

[zrzka]

Related issues I just created:

• Do not generate bindings for dependencies rustwasm/wasm-bindgen#1231 - Do not generate bindings for dependencies
• Add support for additional cargo arguments (wasm-pack test) rustwasm/wasm-pack#538 - Add support for additional cargo arguments (wasm-pack test)

[cyplo]

some good research here :)