Implement runtime display (test) (#318)

* Implement runtime display (test)

* Update runtime.cpp

* [game display] add "-nodisplay" argument

* style fixes

* Update gfx.cpp

* [deci2server] fix deadlock when killing a Deci2Server

* add libxrandr to linux github test

* correct package name to libxrandr-dev

* set g_main_thread_id in exec_runtime

* add libxinerama to linux test packages

* correct the name

* add libxcursor1 package

* Update linux-workflow.yaml

* add libxi-dev

* fix constructor for g_main_thread_id

* fix submodules + use -nodisplay during tests

* move the gfx loop to its own function and use a lambda for exit conditions

* fix include

* fix include

* fix includes (for real this time)

game/system/SystemThread.cpp

@@ -68,6 +68,17 @@ void SystemThreadManager::join() {
   }
 }
 
+/*!
+ * Return true if all threads are exiting (manager shutdown)
+ */
+bool SystemThreadManager::all_threads_exiting() {
+  for (int i = 0; i < thread_count; i++) {
+    if (!threads[i].want_exit)
+      return false;
+  }
+  return true;
+}
+
 /*!
  * bootstrap function to call a SystemThread's function
  */