Support WASI (wasmtime wasmer wasmedge)

[Jengro777]

rustup target add wasm32-wasi

cargo build --target wasm32-wasip1 --release

avey@avey river % cargo build --target wasm32-wasip1 --release
   Compiling proc-macro2 v1.0.86
   Compiling unicode-ident v1.0.12
   Compiling cfg-if v1.0.0
   Compiling libc v0.2.153
   Compiling version_check v0.9.4
   Compiling autocfg v1.2.0
   Compiling wasi v0.11.0+wasi-snapshot-preview1
error[E0463]: can't find crate for `core`
  |
  = note: the `wasm32-wasip1` target may not be installed
  = help: consider downloading the target with `rustup target add wasm32-wasip1`

For more information about this error, try `rustc --explain E0463`.
error: could not compile `wasi` (lib) due to 1 previous error
warning: build failed, waiting for other jobs to finish...
error: could not compile `cfg-if` (lib) due to 1 previous error
avey@avey river %