Can't compile with js feature on nightly rustc

[anlumo]

Describe the bug

This is a continuation of #4468, which was closed as not planned for some reason. Wasmer 5.0.0 doesn't compile on nightly rustc on the wasm32-unknown-unknown target any more when the js feature is enabled due to this line:

wasmer/lib/api/src/lib.rs

Line 23 in af6f650

#![cfg_attr(feature = "js", crate_type = "cdylib")]

rustc -vV

rustc 1.84.0-nightly (b8c8287a2 2024-11-03)
binary: rustc
commit-hash: b8c8287a229cd79604aa84c25e1235fc78cd5f2e
commit-date: 2024-11-03
host: x86_64-unknown-linux-gnu
release: 1.84.0-nightly
LLVM version: 19.1.3

Note that nightly is necessary for multithreading support on Web, I can't use stable.