Add a limit to all Win32 message loops #28

This works around Waves plugins causing an infinite message loop. Since
we run the loop 30 times per second anyways splitting the loop up into
chunks of 20 shouldn't be an issue.

src/wine-host/editor.h

@@ -35,6 +35,17 @@
 #include "../common/configuration.h"
 #include "utils.h"
 
+/**
+ * The maximum number of Win32 messages to handle per message loop. This is
+ * needed because otherwise some plugins can run into an infinite loop. I've
+ * observed this with:
+ *
+ * - Waves plugins
+ * - Melda plugins when having multiple editor windows open within a single
+ *   plugin group
+ */
+constexpr int max_win32_messages = 20;
+
 /**
  * Used to store the maximum width and height of a screen.
  */