Include sys/wait.h to avoid compiler warning
Include sys/wait.h to avoid compiler warning

gcc warned about an implicit declaration of function 'wait3'.
Including this header fixes this.

richmonkey/netleveldb,liqiang199105/redis,ideaar/redis,laurencee/redis,ideaar/redis,powerumc/MyRedis,ScottKaiGu/redis,powerumc/MyRedis,StartTheShift/redis-shift,quangnguyen90/redis,Jonavin/redis,oaastest/redis,sidsen/redis,ScottKaiGu/redis,nandhanurrevanth/redis,fanxu/redis,kts12345/redis,laurencee/redis,enginekit/redis,shanegxxiao/redis,nandhanurrevanth/redis,kolonse/redis,crask/redis-cutter,powerumc/MyRedis_old,quangnguyen90/redis,adamweixuan/redis,oaastest/redis,liqiang199105/redis,adamweixuan/redis,jacklee0810/redis,erwin00776/redis-2.8-optimize,hanmichael/redis,quangnguyen90/redis,kts12345/redis,jacklee0810/redis,shanegxxiao/redis,erwin00776/redis-2.8-optimize,daogangtang/redis_luajit2.6,powerumc/MyRedis_old,Cybermaxs/redis,nandhanurrevanth/redis,grisha/thredis,richmonkey/netleveldb,quangnguyen90/redis,powerumc/MyRedis_old,laurencee/redis,Jonavin/redis,kolonse/redis,miminus/redis,jaambee/redis,sidsen/redis,enginekit/redis,miminus/redis,jacklee0810/redis,janeasystems/redis,quangnguyen90/redis,alpha8/redis,shanegxxiao/redis,oaastest/redis,kts12345/redis,hanmichael/redis,fanxu/redis,liqiang199105/redis,jaambee/redis,janeasystems/redis,ScottKaiGu/redis,Cybermaxs/redis,jqk6/redis,janeasystems/redis,adamweixuan/redis,powerumc/MyRedis_old,damy/redis,jacklee0810/redis,alpha8/redis,erwin00776/redis-2.8-optimize,damy/redis,liqiang199105/redis,Cybermaxs/redis,hanmichael/redis,jqk6/redis,miminus/redis,ScottKaiGu/redis,ideaar/redis,upsoft/redis,crask/redis-cutter,LittlePeng/redis,jqk6/redis,nandhanurrevanth/redis,laurencee/redis,miminus/redis,DeNA/redis,enginekit/redis,upsoft/redis,janeasystems/redis,kolonse/redis,shanegxxiao/redis,alpha8/redis,Cybermaxs/redis,hanmichael/redis,Jonavin/redis,damy/redis,daogangtang/redis_luajit2.6,kts12345/redis,kolonse/redis,StartTheShift/redis-shift,StartTheShift/redis-shift,LittlePeng/redis,ScottKaiGu/redis,adamweixuan/redis,damy/redis,shanegxxiao/redis,fanxu/redis,hanmichael/redis,adamweixuan/redis,kolonse/redis,jqk6/redis,Cybermaxs/redis,upsoft/redis,alpha8/redis,Jonavin/redis,alpha8/redis,damy/redis,grisha/thredis,daogangtang/redis_luajit2.6,LittlePeng/redis,richmonkey/netleveldb,DeNA/redis,oaastest/redis,oaastest/redis,sidsen/redis,kts12345/redis,laurencee/redis,upsoft/redis,ideaar/redis,erwin00776/redis-2.8-optimize,enginekit/redis,jaambee/redis,powerumc/MyRedis,fanxu/redis,janeasystems/redis,sidsen/redis,liqiang199105/redis,jaambee/redis,jacklee0810/redis,Jonavin/redis,miminus/redis,grisha/thredis,upsoft/redis,daogangtang/redis_luajit2.6,jaambee/redis,richmonkey/netleveldb,ideaar/redis,crask/redis-cutter,DeNA/redis,sidsen/redis,enginekit/redis,sidsen/redis,jqk6/redis,nandhanurrevanth/redis,grisha/thredis