diff --git a/SWIG/Tools/config/ac_define_dir.m4 b/SWIG/Tools/config/ac_define_dir.m4
index e926be9ed..fc81b098c 100644
--- a/SWIG/Tools/config/ac_define_dir.m4
+++ b/SWIG/Tools/config/ac_define_dir.m4
@@ -1,12 +1,35 @@
-dnl Available from the GNU Autoconf Macro Archive at:
-dnl http://www.gnu.org/software/ac-archive/htmldoc/ac_define_dir.html
+dnl @synopsis AC_DEFINE_DIR(VARNAME, DIR [, DESCRIPTION])
 dnl
+dnl This macro sets VARNAME to the expansion of the DIR variable,
+dnl taking care of fixing up ${prefix} and such.
+dnl
+dnl VARNAME is then offered as both an output variable and a C
+dnl preprocessor symbol.
+dnl
+dnl Example:
+dnl
+dnl    AC_DEFINE_DIR([DATADIR], [datadir], [Where data are placed to.])
+dnl
+dnl @category Misc
+dnl @author Stepan Kasal <kasal@ucw.cz>
+dnl @author Andreas Schwab <schwab@suse.de>
+dnl @author Guido Draheim <guidod@gmx.de>
+dnl @author Alexandre Oliva
+dnl @version 2005-07-29
+dnl @license AllPermissive
+
 AC_DEFUN([AC_DEFINE_DIR], [
-  test "x$prefix" = xNONE && prefix="$ac_default_prefix"
-  test "x$exec_prefix" = xNONE && exec_prefix='${prefix}'
-  ac_define_dir=`eval echo [$]$2`
-  ac_define_dir=`eval echo [$]ac_define_dir`
-  ifelse($3, ,
-    AC_DEFINE_UNQUOTED($1, "$ac_define_dir"),
-    AC_DEFINE_UNQUOTED($1, "$ac_define_dir", $3))
+  prefix_NONE=
+  exec_prefix_NONE=
+  test "x$prefix" = xNONE && prefix_NONE=yes && prefix=$ac_default_prefix
+  test "x$exec_prefix" = xNONE && exec_prefix_NONE=yes && exec_prefix=$prefix
+dnl In Autoconf 2.60, ${datadir} refers to ${datarootdir}, which in turn
+dnl refers to ${prefix}.  Thus we have to use `eval' twice.
+  eval ac_define_dir="\"[$]$2\""
+  eval ac_define_dir="\"$ac_define_dir\""
+  AC_SUBST($1, "$ac_define_dir")
+  AC_DEFINE_UNQUOTED($1, "$ac_define_dir", [$3])
+  test "$prefix_NONE" && prefix=NONE
+  test "$exec_prefix_NONE" && exec_prefix=NONE
 ])
+