--- polyml.5.4.1-orig/configure.ac	2010-09-03 21:22:40.000000000 +1000
+++ polyml.5.4.1/configure.ac	2012-01-09 22:44:04.153668402 +1100
@@ -321,7 +321,7 @@
 AC_ARG_WITH([portable],
     [AS_HELP_STRING([--with-portable],
               [Build the portable interpreter version of Poly/ML instead of native @<:@default=no@:>@])], [
-    ac_cv_with_portable=yes], [
+    ac_cv_with_portable="$withval"], [
     ac_cv_with_portable=no])
 
 case "${host_cpu}" in
