diff -rauN Macaulay2-1.3.1-r10737.xdg_open/configure.ac Macaulay2-1.3.1-r10737-prefix/configure.ac
--- Macaulay2-1.3.1-r10737.xdg_open/configure.ac	2010-02-17 09:25:39.000000000 +0000
+++ Macaulay2-1.3.1-r10737-prefix/configure.ac	2010-02-17 09:26:36.000000000 +0000
@@ -1312,7 +1312,7 @@
 	   eval  pre_${i}=`echo $v | sed s,"^$prefix","'\\${pre_prefix}'",`
 	   eval      ${i}=`echo $v | sed s,"^$prefix","'\\${prefix}'",`
 	   ;;
-     *) AC_MSG_ERROR([expected "\${$i}" => "$w" to start with "\${prefix}" or with "\${exec_prefix}"]) ;;
+     *) AC_MSG_NOTICE([expected "\${$i}" => "$w" to start with "\${prefix}" or with "\${exec_prefix}"]) ;;
    esac
 done
 prefix=$save_prefix