Fix is from upstream:
https://github.com/milkytracker/MilkyTracker/commit/7afd55c42ad80d01a339197a2d8b5461d214edaf

Gentoo Bug: https://bugs.gentoo.org/711280

commit 7afd55c42ad80d01a339197a2d8b5461d214edaf
Author: Jeremy Clarke <geckojsc@gmail.com>
Date:   Mon Apr 13 23:53:51 2020 +0100

    Fix use-after-free in PlayerGeneric destructor

diff --git a/src/milkyplay/PlayerGeneric.cpp b/src/milkyplay/PlayerGeneric.cpp
index 8df2c13..59f7cba 100644
--- a/src/milkyplay/PlayerGeneric.cpp
+++ b/src/milkyplay/PlayerGeneric.cpp
@@ -202,15 +202,16 @@ PlayerGeneric::PlayerGeneric(mp_sint32 frequency, AudioDriverInterface* audioDri
 	
 PlayerGeneric::~PlayerGeneric()
 {
-	if (mixer)
-		delete mixer;
 
 	if (player)
 	{
-		if (mixer->isActive() && !mixer->isDeviceRemoved(player))
+		if (mixer && mixer->isActive() && !mixer->isDeviceRemoved(player))
 			mixer->removeDevice(player);
 		delete player;
 	}
+	
+	if (mixer)
+		delete mixer;
 
 	delete[] audioDriverName;