diff --git a/gnu/packages/linux.scm b/gnu/packages/linux.scm
index f2d45eb07a..9a8bbc78d8 100644
--- a/gnu/packages/linux.scm
+++ b/gnu/packages/linux.scm
@@ -4675,7 +4675,7 @@ (define-public thinkfan
                     (share (string-append out "/share/" ,name)))
                (substitute* "CMakeLists.txt"
                  (("pkg_check_modules\\((OPENRC|SYSTEMD) .*" _ package)
-                  (format "option(~a_FOUND \"Faked\" ON)\n" package))
+                  (format #f "option(~a_FOUND \"Faked\" ON)\n" package))
                  ;; That was easy!  Now we just need to fix the destinations.
                  (("/etc" directory)
                   (string-append out directory)))