diff --git a/ChangeLog b/ChangeLog
index 5a1e806..50b6bee 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2021-01-31  Bruno Haible  <bruno@clisp.org>
 
+	Update after gnulib changed on 2020-08-26.
+	* configure.ac: Test $iconv_arg1, not $am_cv_proto_iconv_arg1.
+
+2021-01-31  Bruno Haible  <bruno@clisp.org>
+
 	Switch to autoconf 2.71.
 	* autogen.sh: Update comment.
 	* configure.ac: Use AS_HELP_STRING instead of AC_HELP_STRING. Invoke
diff --git a/configure.ac b/configure.ac
index 43ec5ca..6fe4a7e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -105,7 +105,7 @@
 
 dnl           checks for header files, functions and declarations
 
-if test "$am_cv_func_iconv" = yes -a -n "$am_cv_proto_iconv_arg1"; then
+if test "$am_cv_func_iconv" = yes -a -n "$iconv_arg1"; then
   ICONV_CONST="const"
 else
   ICONV_CONST=""