newline, then it all goes horribly wrong when make tries to terminate
the last input line.
This was all ok before the mmap changes (rev 1.169) because the last
32 bytes of the input buffer were never read into.
The non-mmap case has a similar problem.
Bug found because my .depend files don't have a newline at the end of
the .OPTIO|NAL line (don't know if that is a local change).
c5191c6734