Merge pull request #3655 from zimbatm/hash-encoding-prepare

perl/lib/Nix/Store.xs

src/libexpr/primops/fetchTree.cc

src/libfetchers/fetchers.cc

src/libfetchers/tarball.cc

src/libstore/build.cc

src/libstore/export-import.cc

src/libstore/local-store.cc

src/libstore/nar-info-disk-cache.cc

src/libstore/nar-info.cc

src/libstore/optimise-store.cc

src/libstore/store-api.cc

src/libutil/hash.hh

src/libutil/tests/hash.cc

src/nix-store/nix-store.cc

src/nix/verify.cc