now the default_syscall points to NULL,
- an alternateve default_syscal which is used to output error information is added into f.c (no component should make a Linux syscall, we want to find out any component does it)
- I need to rewite the 'call cos_syscall ... ' statement in syscall.S, the correct way to write that, reference to ipc.S, 408
fixed the function calling in i386/syscall.h
sync with sega