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] next goal: rounded (user goal)
[__0] rejecting: rounded-1.0 (conflict: pkg-config package mpfr>=4.0.0, not
found in the pkg-config database)
[__0] rejecting: rounded-0.2, rounded-0.1.0.1, rounded-0.1 (constraint from
user target requires ==1.0)
[__0] fail (backjumping, conflict set: rounded)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: rounded