Merge issue #12973 list_repeat fix.

diff --cc Misc/NEWS
index c786d24a4d816b632911f55bddbe1cacc4ba0308,bc52aa8ae983e6ad6e60e3937f921cc393bb02de..72e1a0c8db5f2f65f119bf98c582bb2d7d2c9170
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -10,9 -10,10 +10,13 @@@ What's New in Python 3.3 Alpha 1
  Core and Builtins
  -----------------
  
+ - Issue #12973: Fix overflow check that relied on undefined behaviour in
+   list_repeat.  This bug caused test_list to fail with recent versions
+   of Clang.
+ 
 +- Issue #12904: os.utime, os.futimes, os.lutimes, and os.futimesat now write
 +  atime and mtime with nanosecond precision on modern POSIX platforms.
 +
  - Issue #12802: the Windows error ERROR_DIRECTORY (numbered 267) is now
    mapped to POSIX errno ENOTDIR (previously EINVAL).
  

diff --cc Objects/listobject.c
Simple merge