The build is unreachable.

Build log

> /tmp/stackage-build2451$ stack unpack xxhash-ffi-0.2.0.0@sha256:0b4c4fc2730dcfd5216be19a4a00bac172bcd522b18777dab23fda954feedf96
Unpacked xxhash-ffi-0.2.0.0 to /tmp/stackage-build2451/xxhash-ffi-0.2.0.0/
> /tmp/stackage-build2451/xxhash-ffi-0.2.0.0$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
[1 of 1] Compiling Main             ( Setup.hs, Setup.o )
Linking Setup ...
> /tmp/stackage-build2451/xxhash-ffi-0.2.0.0$ ./Setup configure --package-db=clear --package-db=global --package-db=/home/circleci/project/builds/nightly/pkgdb --libdir=/home/circleci/project/builds/nightly/lib --bindir=/home/circleci/project/builds/nightly/bin --datadir=/home/circleci/project/builds/nightly/share --libexecdir=/home/circleci/project/builds/nightly/libexec --sysconfdir=/home/circleci/project/builds/nightly/etc --docdir=/home/circleci/project/builds/nightly/doc/xxhash-ffi-0.2.0.0 --htmldir=/home/circleci/project/builds/nightly/doc/xxhash-ffi-0.2.0.0 --haddockdir=/home/circleci/project/builds/nightly/doc/xxhash-ffi-0.2.0.0
Configuring xxhash-ffi-0.2.0.0...
> /tmp/stackage-build2451/xxhash-ffi-0.2.0.0$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2451/xxhash-ffi-0.2.0.0$ ./Setup build
Preprocessing library for xxhash-ffi-0.2.0.0..
Building library for xxhash-ffi-0.2.0.0..
[1 of 2] Compiling Data.Digest.XXHash.FFI.C ( dist/build/Data/Digest/XXHash/FFI/C.hs, dist/build/Data/Digest/XXHash/FFI/C.o )
[2 of 2] Compiling Data.Digest.XXHash.FFI ( src/Data/Digest/XXHash/FFI.hs, dist/build/Data/Digest/XXHash/FFI.o )
> /tmp/stackage-build2451/xxhash-ffi-0.2.0.0$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2451/xxhash-ffi-0.2.0.0$ ./Setup copy
Installing library in /home/circleci/project/builds/nightly/lib/x86_64-linux-ghc-8.7.20181114/xxhash-ffi-0.2.0.0-Dy3FxGaOmUk4EErDV74iL1
> /tmp/stackage-build2451/xxhash-ffi-0.2.0.0$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2451/xxhash-ffi-0.2.0.0$ ./Setup register
Registering library for xxhash-ffi-0.2.0.0..