diff --git a/tool/rbinstall.rb b/tool/rbinstall.rb
index 624961b4ee..0d0f6b2f79 100755
--- a/tool/rbinstall.rb
+++ b/tool/rbinstall.rb
@@ -853,9 +853,6 @@ module RbInstall
     def write_cache_file
     end
 
-    def build_extensions
-    end
-
     def shebang(bin_file_name)
       path = File.join(gem_dir, spec.bindir, bin_file_name)
       first_line = File.open(path, "rb") {|file| file.gets}