mhlsbr.c: Don't read(2) from fileno(3) of stdout.

mhlsbr.c: Don't read(2) from fileno(3) of stdout.

Remove the assumption that file descriptor 1 is readable.  It can be if
it, or where it was dup(2)'d from, was opened read/write, e.g. on
/dev/tty.  But it can easily be arranged with shell re-direction that it
isn't, and then the read(2) fails.  Pass 0, standard input's file
descriptor, instead.  Don't use fileno(stdin) as I can't think of a need
to support that being non-zero, but its use makes the reader think it
might.  Bug pre-dates git.