#[cfg_or_panic(..)]

Keep the function body under #[cfg(..)], or replace it with unimplemented!() under #[cfg(not(..))].

Example

```rust use cfgorpanic::cfgorpanic;

[cfgorpanic(feature = "foo")]

fn foo() -> i32 { 42 }

[test]

[cfgattr(not(feature = "foo"), shouldpanic)]

fn test() { assert_eq!(foo(), 42); } ```