diff --git a/gash/compat.scm b/gash/compat.scm
index dae71f4..d3aa64d 100644
--- a/gash/compat.scm
+++ b/gash/compat.scm
@@ -103,7 +103,8 @@
           call-with-input-string
           thunk?
           EXIT_SUCCESS
-          EXIT_FAILURE)
+          EXIT_FAILURE
+          exact-integer?)
 
   (define-macro (define-inlinable . rest)
     `(define ,@rest))
@@ -191,4 +192,7 @@
            (or (null? args) (symbol? args)))))
 
   (define EXIT_SUCCESS 0)
-  (define EXIT_FAILURE 1))
+  (define EXIT_FAILURE 1)
+
+  ;; Mes only has exact integers.
+  (define exact-integer? integer?))