"empty" should require /dev/pts to work in hasher; like dejagnu does:

$ apt-cache showpkg /dev/pts
Package: /dev/pts
Versions: 

Reverse Depends: 
  dejagnu,/dev/pts
Dependencies: 
Provides: 
Reverse Provides: 
filesystem 2.3.18-alt1:sisyphus+257426.100.1.1@1599226664
dev-minimal 3.3.1-alt23:sisyphus+269283.100.1.1@1617964822


Without it, if used in hasher (in some tests in a package), it fails:

$ hsh-install ~/hasher empty && hsh-run ~/hasher -- /bin/sh -c 'empty -f /bin/sh -i; empty -k'
<5>Feb  8 05:31:48 empty: version 0.6.21b started
<5>Feb  8 05:31:48 empty: PTY routine failed. Fatal openpty()
Can't kill PID: 1738115: No such process

With such a dependency, it wouldn't fail:

$ hsh-install ~/hasher empty && hsh-run --mount /dev/pts ~/hasher -- /bin/sh -c 'empty -f /bin/sh -i; empty -k'
<5>Feb  8 05:30:22 empty: version 0.6.21b started
<5>Feb  8 05:30:22 empty: forked /bin/sh -i
<5>Feb  8 05:30:22 empty: /bin/sh exited
<5>Feb  8 05:30:22 empty: version 0.6.21b finished