Issue #18792: Use "127.0.0.1" or "::1" instead of "localhost" as much as possible, since "localhost" goes through a DNS lookup under recent Windows versions.
Issue #18747: Use a parent atfork handler instead of a child atfork handler.
fork() is suppose to be async-signal safe but the handler calls unsafe functions. A parent handler mitigates the issue.
Issue #18747: Update Misc/NEWS to reflect the latest changeset.
Issue #16809: Tkinter's splitlist() and split() methods now accept Tcl_Obj
argument.

This is needed for support Tcl/Tk 8.6.
Issue #16809: Fixed some tkinter incompabilities with Tcl/Tk 8.6.