Warning: The install command is a part of the legacy v1 style of cabal usage.

Please switch to using either the new project style and the new-install
command or the legacy v1-install alias as new-style projects will become the
default in the next version of cabal-install. Please file a bug if you cannot
replicate a working v1- use case with the new-style commands.

For more information, see: https://wiki.haskell.org/Cabal/NewBuild

Resolving dependencies...
cabal: Could not resolve dependencies:
[__0] trying: differential-0.1.1.0 (user goal)
[__1] next goal: inline-r (dependency of differential)
[__1] rejecting: inline-r-0.9.2, inline-r-0.9.1, inline-r-0.9.0.2,
inline-r-0.9.0.1, inline-r-0.9.0.0, inline-r-0.8.0.1, inline-r-0.8.0.0,
inline-r-0.7.3.0, inline-r-0.7.2.0, inline-r-0.7.1.2, inline-r-0.7.1.1,
inline-r-0.7.1.0, inline-r-0.7.0.0 (conflict: pkg-config package libR>=3.0,
not found in the pkg-config database)
[__1] fail (backjumping, conflict set: differential, inline-r)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: inline-r, base, differential