Without this patch, attempts to install at least some of the packages
that start to use setupHaskellDepends (mostly gtk-related packages)
results in collisions:
building path(s) ‘/nix/store/63k5smns43f5r2ad8wcc242x0gwd70m3-ghc-8.0.1’
collision between `/nix/store/k18i1nm5hgnb82y9w2g9hmlwhk3szjld-ghc-8.0.1/lib/ghc-8.0.1/Cabal-1.24.0.0/Distribution/Compat/Binary.dyn_hi' and `/nix/store/0rwhbwsg9kmywgbrib2bs29p2hmi80za-Cabal-1.24.0.0/lib/ghc-8.0.1/Cabal-1.24.0.0/Distribution/Compat/Binary.dyn_hi'
builder for ‘/nix/store/vrjkfpm8sb96m9i5k74h8vn0rwddgy4v-ghc-8.0.1.drv’ failed with exit code 25
This would appear to me to be a consequence of setupHaskellDepends
entries being added to propagateBuildInputs. It is sufficient in the
cases I'm familiar with (taffyBar), and I think correct, to simply add
it to the otherBuildInputs.
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