// An `extern LIB "csym"` reference must name something real, exactly like
// its `extern LIB` twin (example 1620): `nosuchunit` names neither a
// #library constant nor a named `#import c` unit, so this is a compile-time
// diagnostic — the bogus library reference is caught BEFORE the symbol
// would silently resolve through whatever image happens to carry it.
//
// Regression (FFI-linkage Part B): `checkExternRefs` validated only a
// `extern` (extern-import shape) library_ref and skipped the `extern` keyword's
// `extern_lib`, so a bogus `extern` lib reference compiled silently (the
// symbol resolved via the default image and ran). Prerequisite for
// migrating the fn-decl `extern` path onto `extern`.
#import "modules/std.sx";

c_abs :: (n: i32) -> i32 extern nosuchunit "abs";

main :: () -> i32 {
    print("c_abs = {}\n", c_abs(-5));
    0
}