whitelist platforms where panicking should work

Author: RalfJung

src/shims/panic.rs

@@ -43,6 +43,12 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
 
         trace!("miri_start_panic: {:?}", this.frame().span);
 
+        // Make sure panicking actually works on this platform.
+        match this.tcx.sess.target.target.target_os.as_str() {
+            "linux" | "macos" => {},
+            _ => throw_unsup_format!("panicking is not supported on this platform"),
+        }
+
         // Get the raw pointer stored in arg[0] (the panic payload).
         let payload = this.read_scalar(args[0])?.not_undef()?;
         assert!(