I was trying to build this on OS X 10.4 and got a linker error that _console_chan was an undefined symbol. Digging a bit, I discovered that in io/console.c, there is a line that declares:
int console_chan;
but does not make any use of it. My suspicion was that because this value is not bound to a value in the module, it doesn't get allocated any storage and so GCC throws it away, even...