Add no_std support to wasm-encoder

[ark0f]

No description provided.

[alexcrichton]

Thanks for the PR! For posterity can you describe as well how you're planning on using this? (e.g. the platform/use case you have in mind). Also mind updating this comment as well to mention the new build script?

[ark0f]

For posterity can you describe as well how you're planning on using this? (e.g. the platform/use case you have in mind).

Sure. Great part of Gear Protocol business logic is compiled into WASM to be deterministically executed on blockchain and thus we have no_std environment. We want to instrument user uploaded WASM programs with wasmparser and wasm-encoder libraries

[ark0f]

Also mind updating this comment as well to mention the new build script?

Done