Revert "remove spinlocks"

This reverts commit 1670c26313.

src/pongo_helper.c

@@ -25,7 +25,9 @@ void* pongo_helper(void* ptr) {
 	pongo_thr_running = 1;
 	pthread_cleanup_push(thr_cleanup, &pongo_thr_running);
 	wait_for_pongo();
-	palerain_block();
+	while (get_spin()) {
+		sleep(1);
+	}
 	pthread_cleanup_pop(1);
 	return NULL;
 }
@@ -139,7 +141,7 @@ done:
 #ifdef USE_LIBUSB
 	libusb_unref_device(arg->dev);
 #endif
-	palerain_unblock();
+	set_spin(0);
 	return NULL;
 }
 
@@ -234,7 +236,7 @@ void io_start(stuff_t *stuff)
     if(r != 0)
     {
         ERR("pthread_create: %s", strerror(r));
-        palerain_unblock();
+        set_spin(0);
 		return;
     }
     pthread_join(stuff->th, NULL);
@@ -246,14 +248,14 @@ void io_stop(stuff_t *stuff)
     if(r != 0)
     {
         ERR("pthread_cancel: %s", strerror(r));
-        palerain_unblock();
+        set_spin(0);
 		return;
     }
     r = pthread_join(stuff->th, NULL);
     if(r != 0)
     {
         ERR("pthread_join: %s", strerror(r));
-        palerain_unblock();
+        set_spin(0);
 		return;
     }
 #ifdef USE_LIBUSB