bpo-36346: Add Py_DEPRECATED to deprecated unicode APIs (GH-20878)

Co-authored-by: Kyle Stanley <aeros167@gmail.com>
Co-authored-by: Victor Stinner <vstinner@python.org>
(cherry picked from commit 2c4928d37edc5e4aeec3c0b79fa3460b1ec9b60d)
diff --git a/Python/getargs.c b/Python/getargs.c
index 7742428..d4a531a 100644
--- a/Python/getargs.c
+++ b/Python/getargs.c
@@ -1070,6 +1070,9 @@
     case 'u': /* raw unicode buffer (Py_UNICODE *) */
     case 'Z': /* raw unicode buffer or None */
     {
+        // TODO: Raise DeprecationWarning
+_Py_COMP_DIAG_PUSH
+_Py_COMP_DIAG_IGNORE_DEPR_DECLS
         Py_UNICODE **p = va_arg(*p_va, Py_UNICODE **);
 
         if (*format == '#') {
@@ -1109,6 +1112,7 @@
                                   arg, msgbuf, bufsize);
         }
         break;
+_Py_COMP_DIAG_POP
     }
 
     case 'e': {/* encoded string */