(dump_remainder): Flush standard output just before

(dump_remainder): Flush standard output just before
sleeping so that `tail -f' will output partial lines sooner.
This applies only when following the end of a single file.
From Leonard N. Zubkoff <lnz@dandelion.com>.

(file_lines, pipe_lines, pipe_bytes, start_bytes, start_lines, dump_remainder):
Use STDOUT_FILENO instead of `1' in XWRITE calls.