Resolving dependencies...
Starting     happy-1.20.0
Building     happy-1.20.0
Completed    happy-1.20.0
Warning: could not create a symlink in /home/builder/.cabal/bin for happy
because the file exists there already but is not managed by cabal. You can
create a symlink for this executable manually if you wish. The executable file
has been installed at
/home/builder/hackage-server/build-cache/tmp-install/bin/happy