Check that ffi functions override libc or other global namespace C functions

What it does

https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=11155e0af04128f0e867045b28b688ed
In example above, close() function is never called in the code. However, test fails, because this function overrides libc close function and cargo uses it instead of normal close function.
Linter should check extern "C" functions names and signatures on possible collision with existing c functions.

Lint Name

Global-C-Function-Collide

Category

correctness, suspicious

Advantage

• Removes possible undefined behaviour when exposing a C interface

Drawbacks

• Override might be deliberate

Example

struct Dummy{}

impl Dummy {
    #[no_mangle]
    pub extern "C" fn close(_: *mut Self) {
        assert_eq!(0,1);
    }
}

#[cfg(test)]
mod tests {
    #[test]
    fn test() {}
}

The linter should say something like: line 5: exposed function overrides existing function (suggested fix: change function name).

Reproduce the collision with the linked Rust Playground example and confirm that the unused close function affects the test. The issue names no repository files or tests, so identify the Clippy lint entry point and testing location before defining how libc and other global C functions are checked; done means the example emits the proposed diagnostic without incorrectly rejecting deliberate overrides.