Log Message:
libopenmpt: update to 0.6.3.

### libopenmpt 0.6.3 (2022-04-24)

 *  Pitch / Pan Separation and Random Variation instrument properties were not
    resetting properly when seeking, potentially causing instruments to be
    played e.g. at a vastly different pan position compared to playing the
    module continuously.
 *  MED: Stereo samples were not imported correctly.

 *  zlib: Update to v1.2.12 (2022-03-27).