eval: Fix jobwait() to process multiple jobs concurrently

The new event processing architecture changed `jobwait()` semantics: Only one
job is processed at time since process_wait only focuses on one queue.

This fixes the problem with a few changes:

- Allow the event queue polled by `process_wait` to be overriden by a new
  argument.
- Allow the parent queue to be overriden with `queue_replace_parent`
- Create a temporary queue that serves as the parent for all jobs passed to
  `jobwait()`

1 files changed, 6 insertions, 0 deletions

diff --git a/src/nvim/event/queue.c b/src/nvim/event/queue.c
index 3f03dd444e..19eca14144 100644
--- a/src/nvim/event/queue.c
+++ b/src/nvim/event/queue.c
@@ -152,6 +152,12 @@ bool queue_empty(Queue *queue)
   return QUEUE_EMPTY(&queue->headtail);
 }
 
+void queue_replace_parent(Queue *queue, Queue *new_parent)
+{
+  assert(queue_empty(queue));
+  queue->parent = new_parent;
+}
+
 static Event queue_remove(Queue *queue)
 {
   assert(!queue_empty(queue));