diff --git a/m4/ac_func_fseeko.m4 b/m4/ac_func_fseeko.m4
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+# This file is part of Autoconf. -*- Autoconf -*-
+# Checking for functions.
+# Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006 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
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
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+# GNU General Public License for more details.
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+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301, USA.
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+# As a special exception, the Free Software Foundation gives unlimited
+# permission to copy, distribute and modify the configure scripts that
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+# source text consists of comments plus executable code that decides which
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+# comments and executable code the "non-data" portions. Autoconf never
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+# the non-data portions to the data portions.) If your modification has
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+#
+# Written by David MacKenzie, with help from
+# Franc,ois Pinard, Karl Berry, Richard Pixley, Ian Lance Taylor,
+# Roland McGrath, Noah Friedman, david d zuhn, and many others.
+
+# AC_FUNC_FSEEKO
+# --------------
+AN_FUNCTION([ftello], [AC_FUNC_FSEEKO])
+AN_FUNCTION([fseeko], [AC_FUNC_FSEEKO])
+AC_DEFUN([AC_FUNC_FSEEKO],
+[_AC_SYS_LARGEFILE_MACRO_VALUE(_LARGEFILE_SOURCE, 1,
+ [ac_cv_sys_largefile_source],
+ [Define to 1 to make fseeko visible on some hosts (e.g. glibc 2.2).],
+ [[#include <sys/types.h> /* for off_t */
+ #include <stdio.h>]],
+ [[int (*fp) (FILE *, off_t, int) = fseeko;
+ return fseeko (stdin, 0, 0) && fp (stdin, 0, 0);]])
+
+# We used to try defining _XOPEN_SOURCE=500 too, to work around a bug
+# in glibc 2.1.3, but that breaks too many other things.
+# If you want fseeko and ftello with glibc, upgrade to a fixed glibc.
+if test $ac_cv_sys_largefile_source != unknown; then
+ AC_DEFINE(HAVE_FSEEKO, 1,
+ [Define to 1 if fseeko (and presumably ftello) exists and is declared.])
+fi
+])# AC_FUNC_FSEEKO