[mktemp] allow empty argument
[mktemp] allow empty argument

jbcrail/coreutils,uutils/coreutils,kevgeniy/coreutils,wimh/coreutils,dbrgn/coreutils,uutils/coreutils,wimh/coreutils,ebfe/coreutils,kwantam/coreutils,jbcrail/coreutils,ebfe/coreutils,Arcterus/coreutils,Arcterus/coreutils,keunwoo/coreutils,tempbottle/coreutils,tempbottle/coreutils,Heather/coreutils,kwantam/coreutils,dbrgn/coreutils,uutils/coreutils,dbrgn/coreutils,keunwoo/coreutils,Heather/coreutils,kevgeniy/coreutils