Re: Command 'diff' visits files prematurely

[Richard Stallman]

    Command 'diff' visits compared files immediately after its invocation,
    which is annoying if user wants to compare large files without visiting
    them (i.e. to see differences only in the *diff* buffer).
    It should visit files only when user calls 'next-error' command.

    Seems, this bug caused by some changes in compile.el.
    This worked correctly in earlier Emacs versions.

That change in compile.el was meant to solve a problem,
but it causes several other problems.  So I will undo it.