`cargo build` failed on nightly

[Taowyoo]

Env:

$ rustc --version
rustc 1.69.0-nightly (75a0be98f 2023-02-05)
$ rustup --version
rustup 1.25.2 (17db695f1 2023-02-01)
info: This is the version for the rustup toolchain manager, not the rustc compiler.
info: The currently active `rustc` version is `rustc 1.69.0-nightly (75a0be98f 2023-02-05)`
$ cargo --version
cargo 1.69.0-nightly (e84a7928d 2023-01-31)

Just 5 days ago, the nightly merged: rust-lang/rust#102513
which make reference to packed field is unaligned a hard error.
So so code change is needed to fix this.