diff --git a/Library/Homebrew/extend/os/linux/formula.rb b/Library/Homebrew/extend/os/linux/formula.rb
index 26bf1d9c68..e1562909aa 100644
--- a/Library/Homebrew/extend/os/linux/formula.rb
+++ b/Library/Homebrew/extend/os/linux/formula.rb
@@ -24,12 +24,5 @@ class Formula
 
       allowed_missing_libraries.merge(libraries)
     end
-
-    undef allowed_missing_libraries
-
-    # @private
-    def allowed_missing_libraries
-      @allowed_missing_libraries ||= Set.new
-    end
   end
 end
diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index e65b08adc3..f307705323 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -2763,7 +2763,7 @@ class Formula
 
     # @private
     def allowed_missing_libraries
-      raise NotImplementedError, "#{__method__} is available on Linux only"
+      @allowed_missing_libraries ||= Set.new
     end
   end
 end