--- ruby-1.9.3-p374/lib/mkmf.rb~	2013-01-22 20:53:15.540519475 +0000
+++ ruby-1.9.3-p374/lib/mkmf.rb	2013-01-22 20:54:46.082573376 +0000
@@ -2041,7 +2041,7 @@
       end
       for f in files
         dest = "#{dir}/#{File.basename(f)}"
-        mfile.print("install-rb#{sfx}: #{dest} #{dir}\n")
+        mfile.print("install-rb#{sfx}: #{dest} #{timestamp_file(dir)}\n")
         mfile.print("#{dest}: #{f}\n")
         mfile.print("\t$(Q) $(#{$extout ? 'COPY' : 'INSTALL_DATA'}) #{f} $(@D#{sep})\n")
         if defined?($installed_list) and !$extout