Don't output '\0' in "@@FINISHED\0".
Cast code to unsigned int. This helps platforms with 16-bit int, by
doing only the low 16 bits of the bitwise-and. It also removes the
"(warning) conversion of long to pointer loses accuracy".
was nearly useless; lots of fixes to qemuppc and pc86 sbrk(), which was broken;
change the pc86 console to echo output to the serial port (needed for running
tests on qemu).
