Description:
------------
When using STR_PAD_BOTH with str_pad(), if there is a tie (i.e. an even/odd length mismatch), the tie will be broken using the default value: adding the string to the right.

There should be a way to force str_pad() to break the tie to left, so that the left side has one more of the string than the right side.

Perhaps add STR_PAD_BOTH_LEFT=3 and alias STR_PAD_BOTH=2 to STR_PAD_BOTH_RIGHT=2.

Test script:
---------------
<?php

define( 'STR_PAD_BOTH_RIGHT', STR_PAD_BOTH ); // 2
define( 'STR_PAD_BOTH_LEFT', 3 );

echo str_pad( '2', 4, ' ', STR_PAD_RIGHT ) . "\n";      // '2   '
echo str_pad( '2', 4, ' ', STR_PAD_LEFT ) . "\n";       // '   2'
echo str_pad( '2', 4, ' ', STR_PAD_BOTH ) . "\n";       // ' 2  '
echo str_pad( '2', 4, ' ', STR_PAD_BOTH_RIGHT ) . "\n"; // ' 2  '
echo str_pad( '2', 4, ' ', STR_PAD_BOTH_LEFT ) . "\n";  // '  2 '

?>

Expected result:
----------------
2   
   2
 2  
 2  
  2 

Actual result:
--------------
2   
   2
 2  
 2  

Warning: str_pad(): Padding type has to be STR_PAD_LEFT, STR_PAD_RIGHT, or STR_PAD_BOTH in str_pad.php on line 10