// One of two flat authors of `absval`, an `extern` libc binding — the
// `extern` twin of example 0729's `extern libc "abs"`. A consumer
// flat-importing BOTH must NOT see this as an ambiguous bare-call
// collision: extern authors (external C symbols) are excluded from the
// bare-call ambiguity verdict, exactly like their `extern` twins.
absval :: (n: i32) -> i32 extern libc "abs";