1 files changed, 1 insertions, 0 deletions

diff --git a/ext/Setup b/ext/Setup
index d0d6317a5e..c7c419f687 100644
--- a/ext/Setup
+++ b/ext/Setup
@@ -20,6 +20,7 @@
 #pty
 #openssl
 #racc/cparse
+#rational
 #readline
 #sdbm
 #socket