Note up front: there is a win32 function wsprintf() and an ISO C
function swprintf(), these are different things in case you wonder.

In _winreg.c, there are two functions that use wsprintf on a char
buffer, while the function takes a TCHAR buffer instead. This leads to
compile warning and runtime errors when _UNICODE is defined, like e.g.
under MS Windows CE. The attached patch replaces the two calls to that
function with calls to fprintf() and PyString_FromFormat().