diff --git a/Library/Homebrew/compat/os/mac.rb b/Library/Homebrew/compat/os/mac.rb
index 7f6cd7ebf6..b94b744b90 100644
--- a/Library/Homebrew/compat/os/mac.rb
+++ b/Library/Homebrew/compat/os/mac.rb
@@ -1,14 +1,14 @@
 module OS
   module Mac
-    module Compat
-      module_function
-
-      def prefer_64_bit?
-        odeprecated("MacOS.prefer_64_bit?")
-        Hardware::CPU.is_64_bit?
+    class << self
+      module Compat
+        def prefer_64_bit?
+          odeprecated("MacOS.prefer_64_bit?")
+          Hardware::CPU.is_64_bit?
+        end
       end
-    end
 
-    prepend Compat
+      prepend Compat
+    end
   end
 end