diff --git a/ext/socket/extconf.rb b/ext/socket/extconf.rb
index 24eb736af0..5138d34008 100644
--- a/ext/socket/extconf.rb
+++ b/ext/socket/extconf.rb
@@ -298,7 +298,7 @@ end
 have_header("sys/un.h")
 have_header("sys/uio.h")
 
-$distcleanfiles << "constants.h"
+$distcleanfiles.concat << "constants.h" << "constdefs.*"
 
 if have_func(test_func)
   have_func("hsterror")