Use ':' instead of ';' to split audio/renderer backends
Use ':' instead of ';' to split audio/renderer backends

cmake uses ';' to split lists, which makes it a pain to work with

FranciscoDA/OpenApoc,ShadowDancer/OpenApoc,pmprog/OpenApoc,steveschnepp/OpenApoc,FranciscoDA/OpenApoc,pmprog/OpenApoc,agry/x-com,agry/x-com,AndO3131/OpenApoc,Istrebitel/OpenApoc,Istrebitel/OpenApoc,FranciscoDA/OpenApoc,steveschnepp/OpenApoc,AndO3131/OpenApoc,agry/x-com,ShadowDancer/OpenApoc,AndO3131/OpenApoc