Initial commit for core dump.

We can create a dummy core file when gpe occurs.
	modified:   executer/kernel/mcctrl.h
	modified:   executer/kernel/syscall.c
	modified:   kernel/include/syscall.h
	modified:   kernel/mem.c

kernel/include/syscall.h

@@ -223,4 +223,5 @@ enum {
 #undef	SYSCALL_HANDLED
 #undef	SYSCALL_DELEGATED
 
+#define	__NR_coredump 999	/* pseudo syscall for coredump */
 #endif