1 files changed, 3 insertions, 2 deletions
diff --git a/missing/finite.c b/missing/finite.c
index f91035a8cd..ab7686317b 100644
--- a/missing/finite.c
+++ b/missing/finite.c
@@ -1,8 +1,9 @@
 /* public domain rewrite of finite(3) */
 
+#include "ruby/missing.h"
+
 int
-finite(n)
-    double n;
+finite(double n)
 {
     return !isnan(n) && !isinf(n);
 }