[libvirt] Question about VIR_ALLOC vs vshMalloc

I was wondering what the reason was for seemingly near-duplicate code. VIR_ALLOC and vshMalloc (and similar methods for calloc, etc), seem to be roughly identical in function, with the only difference being that VIR_ALLOC and friends are used in libvirt proper, whereas vshMalloc and friends are used in the virsh code. Is there a reason why virsh does not simply use VIR_ALLOC and friends? Best Regards, Solly Ross