Fix /dev/random problem: add initial value for status in waitpid()
Fix /dev/random problem: add initial value for status in waitpid()

It seems that if there's no child process terminated, waitpid won't set status.
This will cause problem when status=0 initially, which is the case on the server
Also explains why everything is ok locally, where initail value of status is some random number

BNUACM/bnuoj-backend,BNUACM/bnuoj-backend,crccw/bnuoj-backend,crccw/bnuoj-backend,crccw/bnuoj-backend,BNUACM/bnuoj-backend