Long ago, there was a fourth stdio default stream, stddbg, connected to the
debug console. It has since been replaced by the dbgputstr() and dbgputch()
syscalls.
3fce2fb205
Remove the last remains of stddbg, as fd 3 is soon going to be reused for socket
takeover.
When using the bounded string operations (e.g. snprintf), the null
terminator was always being written even if there was no space for
it (or indeed any valid buffer at all)
This overwriting caused segmentation faults and memory corruption
Furthermore, fread() has already handled EOF, so there's no need to do
it again. If we read a character, return it, otherwise return EOF.
Note that EOF means "EOF or error" here.
The "stddbg" stream was a cute idea but we never ended up using it in
practice, so let's simplify this and implement userspace dbgprintf() on top
of a simple dbgputch() syscall instead.
This makes debugging LibC startup a little bit easier. :^)
