Throw an internal exception when a builtin cannot be registered
Throw an internal exception when a builtin cannot be registered

nathanielbaxter/libminizinc,jjdekker/libminizinc,tias/libminizinc,nathanielbaxter/libminizinc,jjdekker/libminizinc,tias/libminizinc,nathanielbaxter/libminizinc,jjdekker/libminizinc,jjdekker/libminizinc,nathanielbaxter/libminizinc