test: Ignore compile-fail/issue-5806.rs

Broken on BSD. rust-lang#12460

Author: brson

src/test/compile-fail/issue-5806.rs

@@ -18,6 +18,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// ignore-test FIXME #12460
+
 #[path = "../compile-fail"]
 mod foo; //~ ERROR: illegal operation on a directory