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.

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Resolving dependencies...
cabal: Could not resolve dependencies:
[__0] trying: reactive-banana-gi-gtk-0.4.0.2 (user goal)
[__1] trying: haskell-gi-base-0.23.0 (dependency of reactive-banana-gi-gtk)
[__2] next goal: gi-gtk (dependency of reactive-banana-gi-gtk)
[__2] rejecting: gi-gtk-4.0.1 (conflict: reactive-banana-gi-gtk =>
gi-gtk>=3.0.1.1 && <3.1)
[__2] rejecting: gi-gtk-3.0.32 (conflict: pkg-config package gtk+-3.0-any, not
found in the pkg-config database)
[__2] rejecting: gi-gtk-3.0.31, gi-gtk-3.0.30 (conflict:
haskell-gi-base==0.23.0, gi-gtk => haskell-gi-base>=0.22.0 && <0.23)
[__2] rejecting: gi-gtk-3.0.29, gi-gtk-3.0.28 (conflict:
haskell-gi-base==0.23.0, gi-gtk => haskell-gi-base>=0.21.0 && <0.23)
[__2] rejecting: gi-gtk-3.0.27, gi-gtk-3.0.26, gi-gtk-3.0.25, gi-gtk-3.0.24,
gi-gtk-3.0.23, gi-gtk-3.0.22, gi-gtk-3.0.21, gi-gtk-3.0.20, gi-gtk-3.0.19
(conflict: haskell-gi-base==0.23.0, gi-gtk => haskell-gi-base==0.21.*)
[__2] rejecting: gi-gtk-3.0.18, gi-gtk-3.0.17, gi-gtk-3.0.16, gi-gtk-3.0.15,
gi-gtk-3.0.14, gi-gtk-3.0.13, gi-gtk-3.0.12, gi-gtk-3.0.11, gi-gtk-3.0.10,
gi-gtk-3.0.9, gi-gtk-3.0.8, gi-gtk-3.0.7, gi-gtk-3.0.6, gi-gtk-3.0.5,
gi-gtk-3.0.4, gi-gtk-3.0.3, gi-gtk-3.0.2 (conflict: pkg-config package
gtk+-3.0-any, not found in the pkg-config database)
[__2] rejecting: gi-gtk-3.0.1, gi-gtk-0.3.18.15, gi-gtk-0.3.18.14,
gi-gtk-0.3.18.13, gi-gtk-0.3.18.12, gi-gtk-0.3.16.12, gi-gtk-0.3.18.10,
gi-gtk-0.3.16.11, gi-gtk-0.3.16.10, gi-gtk-0.3.16.9, gi-gtk-0.3.16.8
(conflict: reactive-banana-gi-gtk => gi-gtk>=3.0.1.1 && <3.1)
[__2] fail (backjumping, conflict set: gi-gtk, haskell-gi-base,
reactive-banana-gi-gtk)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: gi-gtk, reactive-banana-gi-gtk,
haskell-gi-base, base