Hi!

When using Emacs in a terminal that supports 256 colors (such as the
built-in terminal on macOS), the faces diff-added and diff-removed look the
same.

They are defined to have a background color of #eeffee and #ffeeee,
respectively, in light background mode. When a diff is viewed in a
terminal, they are both rendered using light grey background, so it's
impossible to distinguish between them.

In Emac 26, they were defined using #ddffdd and #ffdddd, respectively,
which is rendered fine in the terminal (on both Emacs 26 and 27).

One way to solve this is to add alternative color definitions using the
"min-colors" requirement. Another is to go back to the old values.

     -- Anders Lindgren

In GNU Emacs 27.0.50 (build 1, x86_64-apple-darwin16.7.0, NS appkit-1504.83
Version 10.12.6 (Build 16G29))
 of 2019-05-01 built on mbp.lan
Repository revision: 7dafbe3ab91e838803a84ab388bca03ff985e312
Repository branch: master
System Description:  Mac OS X 10.12.6

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
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Configured using:
 'configure --with-gnutls=no'

Configured features:
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Load-path shadows:
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Memory information:
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