ediff-diff-ok-lines-regexp

ediff-diff-ok-lines-regexp is a variable defined in `ediff-diff.el'.
Its value is

"^\\([0-9,]+[acd][0-9,]+
?$\\|[<>] \\|---\\|.*Warning *:\\|.*No +newline\\|.*missing +newline\\|^
?$\\)"

Documentation:
Regexp that matches normal output lines from `ediff-diff-program'.
This is mostly lifted from Emerge, except that Ediff also considers
warnings and `Missing newline'-type messages to be normal output.
Lines that do not match are assumed to be error messages.