Non-graphic 3-sided merge tool

Question

I am currently using the RCS merge command for 3-way merges, but one thing has always annoyed me. If I use the -A option, then the same change made in both files appears as a conflict:

<<<<<<< file1
file1 line 1
||||||| orig
orig line 1
=======
file2 line 1
→ → →> file2
orig line 2
& L;
<<<<<< orig =======
line added to both changes
→ → →> file2
orig line 3

If I use the default value (-E), then these same changes are not displayed, but then the output shows only two participants, not the ancestor, something like this:

<<<<<<< file1
file1 line 1
=======
file2 line 1
→ → →> file2
orig line 2
line added to both changes
orig line 3

Is there any program that essentially will do the same behavior as merging RCS, but has a way to show all three versions in conflicts when automatically merging identical changes?

Answer 1

Diff3 seems to have some interesting options.

In ubuntu:

       -m --merge
              Output merged file instead of ed script (default -A).

, vimdiff gvimdiff 3 .

Answer 2

KDiff3 , "--auto", . , , , kdiff3 . ( Windows - ).

( KDiff3, , - .)