Add INCIDENTAL_MUSIC.

data/core/macros/sound-utils.cfg

@@ -325,6 +325,16 @@
     [/event]
 #enddef
 
+#define INCIDENTAL_MUSIC MUSIC
+        # To be played immediately to mark an incident, 
+        # but not appended to the scenario playlist.
+        [music]
+            name={MUSIC}
+            immediate=yes
+            append=no
+        [/music]
+#enddef
+
 # For some animations some units use a list of sounds, from which one is
 # randomly picked every time, instead of a single sound. Here the most commonly
 # used lists are wrapped inside macros.