Description:
------------
If you use the same variable name for prepared statements with in the same block of code a PHP warning is produced and the execute statement will fail on the second prepare statement.

Reproduce code:
---------------
<?php
$db2conn = db2_connect("SAMPLE", "", "");

$query = "Select TABLE_CATALOG, TABLE_NAME From SYSIBM.TABLES";
$stmt = db2_prepare($db2conn, $query);
if(db2_execute($stmt))
{
  $a_result = db2_fetch_both($stmt);
   print("\n" . $a_result[0] . "." . $a_result[1] . "\n\n");
}
db2_free_result($stmt);
db2_free_stmt($stmt);

$query = "Select TABLE_CATALOG, TABLE_NAME From SYSIBM.TABLES";

$stmt = db2_prepare($db2conn, $query);
if(db2_execute($stmt))
{
  $a_result = db2_fetch_both($stmt);
   print("\n" . $a_result[0] . "." . $a_result[1] . "\n\n");
}
db2_free_result($stmt);
db2_free_stmt($stmt);
?>

Expected result:
----------------
SAMPLE.CATALOG


SAMPLE.CATALOG



Actual result:
--------------
SAMPLE.CATALOG


Warning: db2_execute(): More parameters bound than present in C:\testbed\SameNameTest.php on line 18

Warning: db2_execute(): Parameters not bound in C:\testbed\SameNameTest.php on line 18