Long lines and and fileformats

What steps will reproduce the problem?
1. Run this command:
function gen_str { perl -e '@l = "a".."z"; print(join("", 
map($l[int(rand(@l))], 0..('$1' - 1))),"\n") for 0..9'; }; vim -O2 -u NONE -N 
--cmd ':set ffs=unix,dos,mac' <( gen_str 8191) <( gen_str 8192)

What is the expected output? What do you see instead?

Expected: Two panes each with 10 lines.

Observed: On the left one pane with 10 lines. On the right one pane with one 
line and the newlines represented as '^J'.

What version of the product are you using? On what operating system?

I can reproduce the problem with versions 7.4.052 on Ubuntu 14.04 and with 
7.4.617 on Arch Linux.

Please provide any additional information below.

This happens when I open a file with at least one line exceeding 8191 
characters and the option ffs is set to 'unix,dos,mac'.

Original issue reported on code.google.com by tarcisio...@gmail.com on 13 Feb 2015 at 11:08

Merged into: #77

carlo0815 / vim

Long lines and and fileformats #331