Fuzz testing on 32 bits

[RCasatta]

In https://github.com/rust-bitcoin/rust-bitcoin/ we have some potential issues on 32 bits architectures because usize is obviously different on this architecture.

Since 32 bits software could run on 64 bits machine, I would have liked fuzzing with a target different than the host machine, like i686-unknown-linux-gnu but I have seen is not possible to specify a different triplet than the host system with cargo hfuzz

honggfuzz-rs/src/bin/cargo-hfuzz.rs

Line 23 in f45aef1

fn target_triple() -> String {

I would like to know if this is some issue only of how parameters are handled in cargo hfuzz or if there are inherently other issues in the fuzzing process on 32 bits (on a 64 bits host)