Avoid core dump if isql second or third argument is omitted.
diff -Naur mysql-connector-odbc-5.1.5r1144.orig/util/stringutil.c mysql-connector-odbc-5.1.5r1144/util/stringutil.c
--- mysql-connector-odbc-5.1.5r1144.orig/util/stringutil.c 2008-04-14 21:03:35.000000000 -0400
+++ mysql-connector-odbc-5.1.5r1144/util/stringutil.c 2009-02-16 14:28:59.000000000 -0500
@@ -52,7 +52,7 @@
SQLINTEGER i, out_bytes;
my_bool free_str= FALSE;
- if (*len == SQL_NTS)
+ if (str && *len == SQL_NTS)
*len= strlen((char *)str);
if (!str || *len == 0)