Deactivate video vsync for wswan and wswanc emulator
Because of the nature of the original wonderswan hardware to run at 70/75hz, to avoid audio stuttering it is preferred to not have vsync activated.
I've tested (on PC 64bit version of Recalbox) a simple .retroarch.cfg override with the line video_vsync = "false"
and all games run without audio stuttering.