Use PY_FORMAT_SIZE_T because Visual Studio does not understand %zd format.
diff --git a/Python/getargs.c b/Python/getargs.c
index 87b6a6e..bdf1a0c 100644
--- a/Python/getargs.c
+++ b/Python/getargs.c
@@ -373,7 +373,7 @@
         }
         if (iarg != 0) {
             PyOS_snprintf(p, sizeof(buf) - (p - buf),
-                          "argument %zd", iarg);
+                          "argument %" PY_FORMAT_SIZE_T "d", iarg);
             i = 0;
             p += strlen(p);
             while (levels[i] > 0 && i < 32 && (int)(p-buf) < 220) {