simplify Py_UCSN definitions with stdint types

Include/unicodeobject.h

@@ -113,21 +113,9 @@ typedef wchar_t Py_UNICODE;
 
 /* Py_UCS4 and Py_UCS2 are typedefs for the respective
    unicode representations. */
-#if SIZEOF_INT == 4
-typedef unsigned int Py_UCS4;
-#elif SIZEOF_LONG == 4
-typedef unsigned long Py_UCS4;
-#else
-#error "Could not find a proper typedef for Py_UCS4"
-#endif
-
-#if SIZEOF_SHORT == 2
-typedef unsigned short Py_UCS2;
-#else
-#error "Could not find a proper typedef for Py_UCS2"
-#endif
-
-typedef unsigned char Py_UCS1;
+typedef uint32_t Py_UCS4;
+typedef uint16_t Py_UCS2;
+typedef uint8_t Py_UCS1;
 
 /* --- Internal Unicode Operations ---------------------------------------- */