Expand tidy to prevent binaries from being checked

Closes #9621

src/etc/check-binaries.py

@@ -0,0 +1,18 @@
+# Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+# file at the top-level directory of this distribution and at
+# http://rust-lang.org/COPYRIGHT.
+#
+# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+# option. This file may not be copied, modified, or distributed
+# except according to those terms.
+
+import sys
+
+offenders = sys.argv[1:]
+if len(offenders) > 0:
+    print("Binaries checked into src:")
+    for offender in offenders:
+        print(offender)
+    sys.exit(1)