diff --git a/setup.h.in b/setup.h.in
index 1af6276084..fbbfa98dbd 100644
--- a/setup.h.in
+++ b/setup.h.in
@@ -824,6 +824,9 @@
 /* Define if you have the <iconv.h> header file.  */
 #undef HAVE_ICONV_H
 
+/* Test for GLIBC 2.2 iconv() */
+#undef WX_ICONV_TAKES_CHAR
+
 /* Define if you have the <langinfo.h> header file.  */
 #undef HAVE_LANGINFO_H