GROWING UP in Niger, Mdou Moctar listened to traditional Tuareg music. Women played the imzad, a one-stringed fiddle, and the goatskin tindé drum, while men trilled on the shepherd’s flute. Takamba and assouf, guitar-driven styles, were his favourite. “I wanted to play guitar, but couldn’t find one where I lived,” Mr Moctar says via email.…