Description:
------------
When trying to loop 'a' through 'z' using 
for ($i = 'a'; $i < 'z'; $i++)
 print $i;

it loops a-y as it should, but when you try

for ($i = 'a'; $i <= 'z'; $i++)
  print $i;

instead of going a-z it goes a-yz doubling up the letters after a-z

a-z
aa-az
ba-bz
ca-cz
... etc

 I know this breaks under php5, and under php4.

Reproduce code:
---------------
 for ($i = 'a'; $i < 'z'; ++$i)  
 {
   print "$i\n";
 }

and

 for ($i = 'a'; $i <= 'z'; ++$i)  
 {
   print "$i\n";
 }

Expected result:
----------------
abcdefghijklmnopqrstuvwxyz

(seperated by new lines)

Actual result:
--------------
abcdefghijklmnopqrstuvwxyzaaabacadaeaf....yxyyyz