important bug fix for gawk 3.1.3

[Aharon Robbins]

It seems that some critical bug always shows up right after I make a
release.  This patch should be applied to gawk 3.1.3.

Thanks,

Arnold
-----------------------------------
--- ../gawk-3.1.3/eval.c        2003-06-22 01:56:04.000000000 -0700
+++ eval.c      2003-07-09 18:17:05.000000000 -0700
@@ -848,6 +848,7 @@
                        fatal(_("attempt to use array `%s' in a scalar 
context"),
                                array_vname(tree));
                tree->orig_array->type = Node_var;
+               tree->orig_array->var_value = Nnull_string;
                /* fall through */
        case Node_var_new:
                tree->type = Node_var;