syscall: add lots of syscalls

syscall/log.c

@@ -0,0 +1,9 @@
+#include <kernel/printk.h>
+#include <kernel/sched.h>
+
+kern_status_t sys_kern_log(const char *s)
+{
+	struct task *task = current_task();
+	printk("%s: %s", task->t_name, s);
+	return KERN_OK;
+}