diff --git a/ChangeLog b/ChangeLog
index 1e396444..3c52a4a2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2012-01-29  Paul Smith  <psmith@gnu.org>
+
+	* gmk-default.scm (to-string-maybe): Use a more portable way to
+	test for unprintable characters.
+	* configure.in [GUILE]: Guile 1.6 doesn't have pkg-config
+
 2012-01-28  Eli Zaretskii  <eliz@gnu.org>
 
 	* config.h.W32.template: Update from config.h.in.
diff --git a/gmk-default.scm b/gmk-default.scm
index b9161c4e..9aca54a5 100644
--- a/gmk-default.scm
+++ b/gmk-default.scm
@@ -31,8 +31,7 @@
    ((char? x)
     (string x))
    ;; Printable string (no special characters)
-   ((and (string? x)
-         (eq? (string-length (string-delete x char-set:printing)) 0))
+   ((and (string? x) (string-every char-set:printing x))
     x)
    ;; No idea: fail
    (else (error "Unknown object:" x))))