diff --git a/ChangeLog b/ChangeLog
index a79cd37..8ab87bb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
 2010-09-23  Bruno Haible  <bruno@clisp.org>
 
+	Switch to autoconf 2.68.
+	* autogen.sh: Update comment.
+	* configure.ac: Fix AC_COMPILE_IFELSE invocation.
+	* Makefile.devel (AUTOCONF, AUTOHEADER): Switch to version 2.68.
+	* preload/Makefile.devel (AUTOCONF): Likewise.
+
+2010-09-23  Bruno Haible  <bruno@clisp.org>
+
 	* m4/libtool.m4: Update from libtool-2.4, with modifications:
 	2008-04-06  Bruno Haible  <bruno@clisp.org>
 		* m4/libtool.m4 (LT_INIT): When setting LIBTOOL, use
diff --git a/Makefile.devel b/Makefile.devel
index c2c8606..41f0e12 100644
--- a/Makefile.devel
+++ b/Makefile.devel
@@ -4,8 +4,8 @@
 
 SHELL = /bin/sh
 MAKE = make
-AUTOCONF = autoconf-2.67
-AUTOHEADER = autoheader-2.67
+AUTOCONF = autoconf-2.68
+AUTOHEADER = autoheader-2.68
 AUTOMAKE = automake-1.11
 ACLOCAL = aclocal-1.11
 GPERF = gperf
diff --git a/autogen.sh b/autogen.sh
index fe1fb7a..c9ff5e0 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -4,7 +4,7 @@
 # also regenerates all aclocal.m4, config.h.in, Makefile.in, configure files
 # with new versions of autoconf or automake.
 #
-# This script requires autoconf-2.63 and automake-1.11 in the PATH.
+# This script requires autoconf-2.63..2.68 and automake-1.11 in the PATH.
 # It also requires either
 #   - the GNULIB_TOOL environment variable pointing to the gnulib-tool script
 #     in a gnulib checkout, or
diff --git a/configure.ac b/configure.ac
index 3585bd2..72a28fa 100644
--- a/configure.ac
+++ b/configure.ac
@@ -133,8 +133,11 @@
 
 AC_CACHE_CHECK([whether <wchar.h> is standalone],
   [gl_cv_header_wchar_h_standalone],
-  [AC_COMPILE_IFELSE([[#include <wchar.h>
-wchar_t w;]],
+  [AC_COMPILE_IFELSE(
+     [AC_LANG_PROGRAM(
+        [[#include <wchar.h>
+          wchar_t w;]],
+        [[]])],
     [gl_cv_header_wchar_h_standalone=yes],
     [gl_cv_header_wchar_h_standalone=no])])
 if test $gl_cv_header_wchar_h_standalone = yes; then
diff --git a/libcharset/ChangeLog b/libcharset/ChangeLog
index 9736886..0e07ec4 100644
--- a/libcharset/ChangeLog
+++ b/libcharset/ChangeLog
@@ -1,5 +1,11 @@
 2010-09-23  Bruno Haible  <bruno@clisp.org>
 
+	Switch to autoconf 2.68.
+	* autogen.sh: Update comment.
+	* Makefile.devel (AUTOCONF, AUTOHEADER): Switch to version 2.68.
+
+2010-09-23  Bruno Haible  <bruno@clisp.org>
+
 	* m4/libtool.m4: Update from libtool-2.4, with modifications:
 	2008-04-06  Bruno Haible  <bruno@clisp.org>
 		* m4/libtool.m4 (LT_INIT): When setting LIBTOOL, use
diff --git a/libcharset/Makefile.devel b/libcharset/Makefile.devel
index 247e9c7..174cd15 100644
--- a/libcharset/Makefile.devel
+++ b/libcharset/Makefile.devel
@@ -3,8 +3,8 @@
 
 SHELL = /bin/sh
 MAKE = make
-AUTOCONF = autoconf-2.67
-AUTOHEADER = autoheader-2.67
+AUTOCONF = autoconf-2.68
+AUTOHEADER = autoheader-2.68
 ACLOCAL = aclocal-1.11
 CP = cp
 RM = rm -f
diff --git a/libcharset/autogen.sh b/libcharset/autogen.sh
index 37ed7ab..9d30f58 100755
--- a/libcharset/autogen.sh
+++ b/libcharset/autogen.sh
@@ -2,9 +2,9 @@
 # Convenience script for regenerating all aclocal.m4, config.h.in, Makefile.in,
 # configure files with new versions of autoconf or automake.
 #
-# This script requires autoconf-2.63 and automake-1.11 in the PATH.
+# This script requires autoconf-2.63..2.68 and automake-1.11 in the PATH.
 
-# Copyright (C) 2003-2007, 2009 Free Software Foundation, Inc.
+# Copyright (C) 2003-2007, 2009-2010 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/preload/Makefile.devel b/preload/Makefile.devel
index 863d9d8..544059a 100644
--- a/preload/Makefile.devel
+++ b/preload/Makefile.devel
@@ -3,7 +3,7 @@
 
 SHELL = /bin/sh
 MAKE = make
-AUTOCONF = autoconf-2.67
+AUTOCONF = autoconf-2.68
 ACLOCAL = aclocal-1.11
 CP = cp
 RM = rm -f