value->lily-string needs (scm display-lily) module.

Oversight from issue 4474, caused an error when reporting the error in

circled = #(define-music-function (parser location txt) (string?)
  #{ \markup { \circle #txt } #})

\relative c' { c \circled #"1" }

Cf
<URL:http://lists.gnu.org/archive/html/lilypond-user/2015-07/msg00280.html>

diff --git a/scm/ly-syntax-constructors.scm b/scm/ly-syntax-constructors.scm
index a0d35ae92e31b175309f2a7e00089aed0ae4b121..ccf24e0abf74130519a39adaff1a65098b2eeaf5 100644 (file)
--- a/scm/ly-syntax-constructors.scm
+++ b/scm/ly-syntax-constructors.scm
@@ -17,7 +17,8 @@
 
 (define-module (scm ly-syntax-constructors)
   #:use-module (lily)
-  #:use-module (srfi srfi-1))
+  #:use-module (srfi srfi-1)
+  #:use-module (scm display-lily))
 
 (define-public (music-function-call-error fun m)
   (let* ((sigcar (car (ly:music-function-signature fun)))