diff --git a/scheme/link/generate-c-header.scm b/scheme/link/generate-c-header.scm
index 69112b0..9bc95ac 100644
--- a/scheme/link/generate-c-header.scm
+++ b/scheme/link/generate-c-header.scm
@@ -88,9 +88,6 @@
     (let ((name (upcase (car imm))))
       (c-define "S48_~A    (S48_MISC_IMMEDIATE(~D))" name i)))
   (newline)
-  (c-define "S48_ENTER_BOOLEAN(n) ((n) ? S48_TRUE : S48_FALSE)")
-  (c-define "S48_EXTRACT_BOOLEAN(x) ((x) != S48_FALSE)")
-  (newline)
   (c-define "S48_UNSAFE_ENTER_CHAR(c) (S48_CHAR | ((c) << 8))")
   (c-define "S48_UNSAFE_EXTRACT_CHAR(x) ((x) >> 8)")
   (c-define "S48_CHAR_P(x) ((((long) (x)) & 0xff) == S48_CHAR)"))