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] next goal: Allure (user goal)
[__0] rejecting: Allure-0.9.4.1 (constraint from user target requires
==0.9.4.0)
[__0] trying: Allure-0.9.4.0
[__1] next goal: LambdaHack (dependency of Allure)
[__1] rejecting: LambdaHack-0.9.4.1 (conflict: Allure => LambdaHack==0.9.4.0)
[__1] trying: LambdaHack-0.9.4.0
[__2] trying: LambdaHack:-jsaddle
[__3] trying: LambdaHack:-vty
[__4] trying: LambdaHack:-curses
[__5] trying: LambdaHack:-gtk
[__6] next goal: sdl2-ttf (dependency of LambdaHack -curses -gtk -jsaddle
-vty)
[__6] rejecting: sdl2-ttf-2.1.0 (conflict: pkg-config package
SDL2_ttf>=2.0.12, not found in the pkg-config database)
[__6] rejecting: sdl2-ttf-2.0.2, sdl2-ttf-2.0.1, sdl2-ttf-2.0.0 (conflict:
pkg-config package SDL2_ttf>=2.0.0, not found in the pkg-config database)
[__6] rejecting: sdl2-ttf-1.0.0, sdl2-ttf-0.2.2, sdl2-ttf-0.2.1,
sdl2-ttf-0.2.0 (conflict: LambdaHack -curses -gtk -jsaddle -vty =>
sdl2-ttf>=2)
[__6] fail (backjumping, conflict set: LambdaHack, sdl2-ttf,
LambdaHack:curses, LambdaHack:gtk, LambdaHack:jsaddle, LambdaHack:vty)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: Allure, LambdaHack, sdl2-ttf,
LambdaHack:curses, LambdaHack:gtk, LambdaHack:jsaddle, LambdaHack:vty