mktemp: fix parallel installing
Without the upstream patch parallel install fails as:
mktemp> mkdir /nix/store/k5b7wyhwyv9x3z5i6d88y7l1kdrkkfgj-mktemp-1.7/share/man/man1
mktemp> cp: cannot create regular file '/nix/store/k5b7wyhwyv9x3z5i6d88y7l1kdrkkfgj-mktemp-1.7/share/man/man1/1185.tmp': No such file or directory
mktemp> make: *** [Makefile:101: install-man] Error 1
mktemp> make: *** Waiting for unfinished jobs....