[bug-diffutils] bug#63405: Bug in diffutils 3.9 with -D option

[Ralph Campbell]

I'm using Fedora 38 and diffutils 3.9 installed. I also compiled from source and see the same issue.

file1:

Here is some old line.

file2:

Here is some new line.

% diff-3.8 -D NEW file1 file2

#ifndef NEW
Here is some old line.
#else /* NEW */
Here is some new line.
#endif /* NEW */

% diff-3.9 -D NEW file1 file2:

Here is some old line.
Here is some new line.