Output to stdout normally goes to file descriptor 1. However, during
early boot, before the console is opened on file descriptor 1, we also
want printf() to work. So this case is specially treated in
libc/stdio/__stdout_write.cc, where in this early case, we used debug_write
directly, instead of write to the file descriptor.

However, recent patches changed debug_write to write to a memory buffer,
instead of to screen (unless "--verbose" option is given to the loader).
This made early printf() break too.

This patch changes __stdout_write to use console::write(), not
debug_write(). To use console::write(), I had to convert that source
file to C++.

Signed-off-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>