Description:
------------
The documentation states that "item may be an integer value of the 
element or the constant name of the element."
The 2nd way (passing the const name as a string) doesn't work, the 
returned string will always be empty ("").
This may be a documentation bug.

Reproduce code:
---------------
jo@l33t ~> php5 -r '$l = setlocale(LC_ALL, "de_DE.utf8"); printf("%s: %s\n", $l, nl_langinfo(D_T_FMT));'
de_DE.utf8: %a %d %b %Y %T %Z
jo@l33t ~> php5 -r '$l = setlocale(LC_ALL, "de_DE.utf8"); printf("%s: %s\n", $l, nl_langinfo("D_T_FMT"));'
de_DE.utf8:


Expected result:
----------------
Both ways return
de_DE.utf8: %a %d %b %Y %T %Z

Actual result:
--------------
Only when using the D_T_FMT const, the result is like expected.