Macro static_assert

macro_rules! static_assert {
    ($condition:expr) => { ... };
}

Static (aka compile-time) assertion macro.

Ported from rust-lang/rust (MIT/Apache-2.0): https://github.com/rust-lang/rust/blob/432fffa8afb8fcfe658e6548e5e8f10ad2001329/library/std/src/io/error/repr_bitpacked.rs#L352