Added a macro for letting intro music play out

data/core/macros/sound-utils.cfg

@@ -665,6 +665,16 @@
     [/event]
 #enddef
 
+#define LET_INTRO_MUSIC_FINISH
+    # Use immediately following INTRO_AND_SCENARIO_MUSIC, to let the intro music
+    # finish before switching to scenario music.
+    [+event]
+        [+music]
+            immediate=no
+        [/music]
+    [/event]
+#enddef
+
 #define INCIDENTAL_MUSIC MUSIC
     # To be played immediately to mark an incident,
     # but not appended to the scenario playlist.