Use the new Unicode API

 * Replace PyUnicode_FromUnicode(NULL, 0) by PyUnicode_New(0, 0)
 * Replce PyUnicode_FromUnicode(str, len) by PyUnicode_FromWideChar(str, len)
 * Replace Py_UNICODE by wchar_t
 * posix_putenv() uses PyUnicode_FromFormat() to create the string, instead
   of PyUnicode_FromUnicode() + _snwprintf()
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index 4742b44..40a18ed 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -3900,7 +3900,7 @@
     PyObject *result;
 
     if (GetComputerNameExW(ComputerNamePhysicalDnsHostname, buf, &size))
-        return PyUnicode_FromUnicode(buf, size);
+        return PyUnicode_FromWideChar(buf, size);
 
     if (GetLastError() != ERROR_MORE_DATA)
         return PyErr_SetFromWindowsErr(0);