Log Message:
devel/wabt: import wabt-1.0.20.

WABT (we pronounce it "wabbit") is a suite of tools for WebAssembly.

These tools are intended for use in (or for development of) toolchains
or other systems that want to manipulate WebAssembly files. Unlike
the WebAssembly spec interpreter (which is written to be as simple,
declarative and "speccy" as possible), they are written in C/C++
and designed for easier integration into other systems. Unlike
Binaryen these tools do not aim to provide an optimization platform
or a higher-level compiler target; instead they aim for full fidelity
and compliance with the spec (e.g. 1:1 round-trips with no changes
to instructions).