message: add check in spinlocks if another task is ready
diff: #include <hermit/spinlock_types.h>
  #include <hermit/tasks_types.h>
  #include <hermit/errno.h>
  +#include <hermit/tasks.h>
  #include <asm/atomic.h>
  #include <asm/processor.h>
  #include <asm/irqflags.h>
  @@ -103,7 +104,8 @@ inline static int spinlock_lock(spinlock_t* s) {
  #if 1
  ticket = atomic_int32_inc(&s->queue);
  while(atomic_int32_read(&s->dequeue) != ticket) {
  - PAUSE;
  + //PAUSE;
  + check_scheduling();
  }
  s->owner = curr_task->id;
  s->counter = 1;
  @@ -193,7 +195,8 @@ inline static int spinlock_irqsave_lock(spinlock_irqsave_t* s) {
  ticket = atomic_int32_inc(&s->queue);
  while (atomic_int32_read(&s->dequeue) != ticket) {
  - PAUSE;
  + //PAUSE;
  + check_scheduling();
  }
  s->coreid = CORE_ID;
  