nproc: support --all and --ignore and respect OMP_NUM_THREADS
nproc: support --all and --ignore and respect OMP_NUM_THREADS

samfoo/coreutils,Gianbaoluo/coreutils,mauricio/coreutils,beni55/coreutils,tempbottle/coreutils,silvio/rust-coreutils,kball/coreutils,dennis/coreutils,uutils/coreutils,dbrgn/coreutils,Heather/coreutils,keunwoo/coreutils,efuquen/coreutils,kball/coreutils,keunwoo/coreutils,ebfe/coreutils,Arcterus/coreutils,beni55/coreutils,mauricio/coreutils,kwantam/coreutils,hexsel/coreutils,wimh/coreutils,samfoo/coreutils,Shir0kamii/coreutils,polapl/coreutils,uutils/coreutils,dbrgn/coreutils,Gianbaoluo/coreutils,dbrgn/coreutils,Shtong/coreutils,filmor/coreutils,filmor/coreutils,hexsel/coreutils,sshling/coreutils,Heather/coreutils,silvio/rust-coreutils,dennis/coreutils,wimh/coreutils,ebfe/coreutils,retep998/coreutils,efuquen/coreutils,jbcrail/coreutils,Arcterus/coreutils,jbcrail/coreutils,bundai223/coreutils,kevgeniy/coreutils,tempbottle/coreutils,dokaptur/coreutils,kevgeniy/coreutils,steveklabnik/coreutils,sshling/coreutils,uutils/coreutils,Shtong/coreutils,kwantam/coreutils,steveklabnik/coreutils,retep998/coreutils,Shir0kamii/coreutils,polapl/coreutils,bundai223/coreutils