updated for version 7.4.228

Problem:    Compiler warnings when building with Python 3.2.
Solution:   Make type cast depend on Python version. (Ken Takata)

src/if_python.c

@@ -803,6 +803,8 @@ py_memsave(void *p, size_t len)
 # define PY_STRSAVE(s) ((char_u *) py_memsave(s, STRLEN(s) + 1))
 #endif
 
+typedef PySliceObject PySliceObject_T;
+
 /*
  * Include the code shared with if_python3.c
  */