Try fixing ThreadPool issue

Author: akashlevy

.vscode/settings.json

@@ -71,5 +71,6 @@
     "variant": "cpp",
     "algorithm": "cpp",
     "*.inc": "cpp"
-  }
+  },
+  "cmake.sourceDirectory": "/Users/akashlevy/Documents/preqorsor/third_party/yosys/abc"
 }

passes/techmap/abc.cc

@@ -2636,14 +2636,16 @@ struct AbcPass : public Pass {
 			ConcurrentQueue<std::unique_ptr<AbcModuleState>> work_queue(num_worker_threads);
 			ConcurrentQueue<std::unique_ptr<AbcModuleState>> work_finished_queue;
 			ConcurrentStack<AbcProcess> process_pool;
-			ThreadPool worker_threads(num_worker_threads, [&](int){
+			if (num_worker_threads > 0) {
+				ThreadPool worker_threads(num_worker_threads, [&](int){
 					while (std::optional<std::unique_ptr<AbcModuleState>> work =
 							work_queue.pop_front()) {
 						// Only the `run_abc` component is safe to touch here!
 						(*work)->run_abc.run(process_pool);
 						work_finished_queue.push_back(std::move(*work));
 					}
 				});
+			}
 			int state_index = 0;
 			int next_state_index_to_process = 0;
 			std::vector<std::unique_ptr<AbcModuleState>> work_finished_by_index;