wstring support in GCC 4.1.2 in Cygwin 1.5.25-11

Hi All,
I was trying to compile my code on Cygwin[1.5.25-11] with GCC[4.1.2],
but I am not able to build with errors on wstring.
 
I tried to test a simple application which uses wstring, like
 
#include <string>
#include <iostream>
int main( )
{
   using namespace std;
 
 const basic_string <wchar_t> s1 ( L"abc" );
   wstring s2 ( L"abc" );   // Uses the typedef for wstring
   if ( s1 == s2 )
      cout << "The strings s1 & s2 are equal." << endl;
   else
      cout << "The strings s1 & s2 are not equal." << endl;
}
 
and on compiling I am getting the following error..
 
-->g++ main.cpp -o main
main.cpp: In function `int main()':
main.cpp:8: error: `wstring' undeclared (first use this function)
main.cpp:8: error: (Each undeclared identifier is reported only once for each fu
nction it appears in.)
main.cpp:8: error: expected `;' before "s2"
main.cpp:9: error: `s2' undeclared (first use this function)
 
I searched on the net but could not get any thing recent or useful. Some old forum threads[2005] say that
it was not supported.
 
Any advice or pointer will be of great help.
 
Thanks & Regards
Vipin