This patch refactors buf_read_from_socket() into buf_read_from_fd(), and
creates a specialized function for buf_read_from_socket(), which uses
buf_read_from_fd().
See: https://bugs.torproject.org/28179
This patch refactors buf_flush_to_socket() into buf_flush_to_fd() and
creates a specialization function for buf_flush_to_socket() that makes
use of buf_flush_to_fd().
See: https://bugs.torproject.org/28179
Fun fact: these files used to be called log.[ch] until we ran into
conflicts with systems having a log.h file. But now that we always
include "lib/log/log.h", we should be fine.
