Indy4 Amiga features only ROL tracks, thus with
69adb13c2f3cadd4dac2bba8164aa0b8a9400abc the MIDI -> AdLib conversion was
broken. Fixed that now by allowing ROL tracks to be played on AdLib output for
Amiga games.
This probably also affected Monkey Island 2 Amiga, but I don't have it to test.