I plan to implement the subset of sha1sum, sha224sum, sha256sum, sha384sum, sha512sum utils.
My current opinion regarding implementation: since they all will use rust-crypto library, as well as md5sum…
Using commit efb18d9aa5b82414b39668afdd9d975e2906ac3a, I've experienced this build failure in coreutils recently:
```
q[pbuilding man/sha1sum.1
GEN man/runcon.1
[q[pbuilding man/sha224sum.1
…
mv: writing ‘/usr/local/chroots/precise/usr/bin/tabs’: No space left on device
mv: failed to extend ‘/usr/local/chroots/precise/usr/bin/tabs’: No space left on device
mv: writing ‘/usr/local/chroots/p…