consider this code:

	$password = "secret";

	if(CRYPT_MD5)
	{
		$salt = "leonatkinson";
		print("Using MD5: ");
	}
	else
	{
		$salt = "cp";
		print("Using Standard DES: ");
	}

	print(crypt($password, $salt));

On a Solaris box, it appears to work.  On both an NT and a 98 box it gives me "Call to unsupported or undefined function crypt()".  Yet, CRYPT_MD5 appears to be TRUE.  I'm very nearly positive that crypt was working under Windows as recently as 3.0.6, so it looks like it disappeared.  

I also tested the same code under 4b3 and got the same results.

I'm also pretty sure MSVC has crypt, so it makes me suspect there's a bug in the makefile or in a header file.