issing Standard lib in gnat

Hi,

I'm using gnat-4.1 and I found out some standard libs are missing:

try the following sample test:

with Ada.Calendar.Formatting;

procedure test is
begin
         Ada.Text_IO.Put_Line("test");
end test;

And get at compile time:
mscm@[EMAIL PROTECTED]
 gcc -gnat05 -c test.adb
test.adb:1:06: "ada.calendar.formatting" is not a predefined library unit

So is there a lot of missing stuff in gnat?

Sebastien