For some odd APE files, monkey_stringify can be called with a profile value of 0.
This causes us to return Names[-1] which is undefined behaviour. Here's a safe fallback
which at least fixes the crash.

Applies against easytag-1.0 and easytag-1.99.2

--- easytag-1.0/src/libapetag/info_mac.c.orig	2004-12-29 00:57:23.234434264 +0000
+++ easytag-1.0/src/libapetag/info_mac.c	2004-12-29 01:03:58.440353832 +0000
@@ -63,7 +63,10 @@
         "Fast", "Normal", "High", "Extra-High", "Insane"
     };
     unsigned int profile2 = profile/1000;
-    
+
+    if (profile2 == 0)
+        return na;
+
     return (profile2 >= sizeof (Names) / sizeof (*Names)) ? na : Names[(profile2-1)];
 }