Log Message:
fluidsynth: Update to 2.1.3

Changes:

- fix a cross-compilation failure from Win32 to WinARM
- fix issues while fluid_player is seeking
- fix a NULL pointer dereference if synth.dynamic-sample-loading is enabled
- fix a NULL pointer dereference in delete_rvoice_mixer_threads()
- fix a NULL pointer dereference in the soundfont loader
- fix dsound driver playing garbage when terminating fluidsynth
- avoid memory leaks when using libinstpatch