neovim/neovim — pull request #1196 by Shougo (2014-09-18 11:32:05+00:00)
Title: [RFC] vim-patch: 7.4.381

Problem: Get u_undo error when backspacing in Insert mode deletes more than
one line break. (Ayberk Ozgur)
Solution: Also decrement Insstart.lnum.

https://code.google.com/p/vim/source/detail?r=v7-4-381