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...
Starting     co-log-core-0.1.1
Starting     StateVar-1.1.1.1
Building     StateVar-1.1.1.1
Building     co-log-core-0.1.1
Completed    StateVar-1.1.1.1
Starting     colour-2.3.4
Completed    co-log-core-0.1.1
Starting     primitive-0.6.4.0
Building     colour-2.3.4
Building     primitive-0.6.4.0
Completed    colour-2.3.4
Starting     contravariant-1.5
Building     contravariant-1.5
Completed    contravariant-1.5
Starting     ansi-terminal-0.8.2
Building     ansi-terminal-0.8.2
Completed    primitive-0.6.4.0
Starting     vector-0.12.0.1
Building     vector-0.12.0.1
Completed    ansi-terminal-0.8.2
Completed    vector-0.12.0.1
Starting     typerep-map-0.3.0
Building     typerep-map-0.3.0
Completed    typerep-map-0.3.0
Downloading  co-log-0.2.0
Downloaded   co-log-0.2.0
Starting     co-log-0.2.0
Building     co-log-0.2.0
Failed to install co-log-0.2.0
Build log ( /home/builder/.cabal/logs/ghc-8.6.1/co-log-0.2.0-7t4pHpldST16dp7rQhR5T.log ):
cabal: Entering directory '/tmp/cabal-tmp-28009/co-log-0.2.0'
Configuring co-log-0.2.0...
Preprocessing library for co-log-0.2.0..
Building library for co-log-0.2.0..
[1 of 9] Compiling Colog.Actions
[2 of 9] Compiling Colog.Concurrent.Internal
[3 of 9] Compiling Colog.Concurrent
[4 of 9] Compiling Colog.Contra
[5 of 9] Compiling Colog.Monad
[6 of 9] Compiling Colog.Message
[7 of 9] Compiling Colog.Pure
[8 of 9] Compiling Colog.Rotation
[9 of 9] Compiling Colog
Preprocessing executable 'play-colog' for co-log-0.2.0..
Building executable 'play-colog' for co-log-0.2.0..
[1 of 1] Compiling Main
Linking dist/build/play-colog/play-colog ...
Preprocessing executable 'readme' for co-log-0.2.0..
Building executable 'readme' for co-log-0.2.0..
ghc: could not execute: markdown-unlit
cabal: Leaving directory '/tmp/cabal-tmp-28009/co-log-0.2.0'
cabal: Error: some packages failed to install:
co-log-0.2.0-7t4pHpldST16dp7rQhR5T failed during the building phase. The
exception was:
ExitFailure 1