sandbox: Replace use of eventfd with semaphores for synchronization between parent and child (created using clone()
sandbox: Replace use of eventfd with semaphores for synchronization between parent and child (created using clone()

basu96/crux-judge,basu96/crux-judge,basu96/crux-judge,basu96/crux-judge,basu96/crux-judge,CRUx-BPHC/crux-judge,CRUx-BPHC/crux-judge,CRUx-BPHC/crux-judge