syscall: add lots of syscalls

syscall/handle.c

@@ -0,0 +1,8 @@
+#include <kernel/sched.h>
+#include <kernel/syscall.h>
+
+kern_status_t sys_kern_handle_close(kern_handle_t handle)
+{
+	struct task *self = current_task();
+	return task_close_handle(self, handle);
+}