auxdir.m4 patch

[Bruce Korb]

$ diff -u aclocal/auxdir.m4.old aclocal/auxdir.m4
--- aclocal/auxdir.m4.old       Sat Nov  3 13:29:31 2001
+++ aclocal/auxdir.m4   Sat Nov  3 13:31:07 2001
@@ -40,5 +40,5 @@
 
 AC_DEFUN([AM_AUX_DIR_EXPAND], [
 # expand $ac_aux_dir to an absolute path
-am_aux_dir=`CDPATH=:; cd $ac_aux_dir && pwd`
+am_aux_dir=`unset CDPATH || CDPATH=:
cd $ac_aux_dir > /dev/null 2>&1 ; pwd` ])