Issue #18942: sys._debugmallocstats() output was damaged on Windows.

_PyDebugAllocatorStats() called PyOS_snprintf() with a %zd format
code, but MS doesn't support that code.  Interpolated
PY_FORMAT_SIZE_T in place of the "z".

Misc/NEWS

@@ -12,6 +12,8 @@ What's New in Python 3.3.3 release candidate 1?
 Core and Builtins
 -----------------
 
+- Issue #18942: sys._debugmallocstats() output was damaged on Windows.
+
 - Issue #18667: Add missing "HAVE_FCHOWNAT" symbol to posix._have_functions.
 
 - Issue #18368: PyOS_StdioReadline() no longer leaks memory when realloc()

Objects/obmalloc.c

@@ -1761,7 +1761,7 @@ _PyDebugAllocatorStats(FILE *out,
     char buf1[128];
     char buf2[128];
     PyOS_snprintf(buf1, sizeof(buf1),
-                  "%d %ss * %zd bytes each",
+                  "%d %ss * %" PY_FORMAT_SIZE_T "d bytes each",
                   num_blocks, block_name, sizeof_block);
     PyOS_snprintf(buf2, sizeof(buf2),
                   "%48s ", buf1);