--- configure.ac~	2008-09-07 16:53:11.000000000 +0100
+++ configure.ac	2008-09-09 08:49:29.000000000 +0100
@@ -1998,6 +1998,14 @@
 CURL_CHECK_STRUCT_TIMEVAL
 CURL_VERIFY_RUNTIMELIBS
 
+if test x"$ac_cv_sys_file_offset_bits" == "x64"; then
+  if test "${ac_cv_sizeof_large_off_t+set}" = set; then
+    ac_cv_sizeof_off_t=$ac_cv_sizeof_large_off_t
+  else
+    unset ac_cv_sizeof_off_t
+  fi
+fi
+
 AC_CHECK_SIZEOF(size_t)
 AC_CHECK_SIZEOF(int)
 AC_CHECK_SIZEOF(long)