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     StateVar-1.1.1.1
Starting     Only-0.1
Starting     base-orphans-0.8
Starting     base-compat-0.10.5
Building     StateVar-1.1.1.1
Building     Only-0.1
Building     base-orphans-0.8
Building     base-compat-0.10.5
Completed    base-orphans-0.8
Starting     base16-bytestring-0.1.1.6
Completed    StateVar-1.1.1.1
Starting     bytestring-builder-0.10.8.2.0
Completed    Only-0.1
Starting     cabal-doctest-1.0.6
Building     base16-bytestring-0.1.1.6
Building     bytestring-builder-0.10.8.2.0
Building     cabal-doctest-1.0.6
Completed    bytestring-builder-0.10.8.2.0
Starting     cereal-0.5.8.0
Building     cereal-0.5.8.0
Completed    base16-bytestring-0.1.1.6
Starting     cryptohash-sha256-0.11.101.0
Building     cryptohash-sha256-0.11.101.0
Completed    cabal-doctest-1.0.6
Starting     dlist-0.8.0.5
Building     dlist-0.8.0.5
Completed    base-compat-0.10.5
Starting     file-embed-0.0.11
Building     file-embed-0.0.11
Completed    cryptohash-sha256-0.11.101.0
Starting     hashable-1.2.7.0
Building     hashable-1.2.7.0
Completed    dlist-0.8.0.5
Starting     integer-logarithms-1.0.2.2
Building     integer-logarithms-1.0.2.2
Completed    file-embed-0.0.11
Downloading  leancheck-0.9.1
Downloaded   leancheck-0.9.1
Starting     leancheck-0.9.1
Building     leancheck-0.9.1
Completed    cereal-0.5.8.0
Starting     mtl-compat-0.2.1.3
Completed    integer-logarithms-1.0.2.2
Starting     network-2.8.0.0
Building     mtl-compat-0.2.1.3
Completed    mtl-compat-0.2.1.3
Starting     postgresql-libpq-0.9.4.2
Completed    hashable-1.2.7.0
Starting     primitive-0.6.4.0
Building     primitive-0.6.4.0
Failed to install postgresql-libpq-0.9.4.2
Build log ( /home/builder/.cabal/logs/ghc-8.6.3/postgresql-libpq-0.9.4.2-HyacS45qPUc33pszxfYdpM.log ):
cabal: Entering directory '/tmp/cabal-tmp-30851/postgresql-libpq-0.9.4.2'
[1 of 1] Compiling Main             ( /tmp/cabal-tmp-30851/postgresql-libpq-0.9.4.2/dist/setup/setup.hs, /tmp/cabal-tmp-30851/postgresql-libpq-0.9.4.2/dist/setup/Main.o )
Linking /tmp/cabal-tmp-30851/postgresql-libpq-0.9.4.2/dist/setup/setup ...
Configuring postgresql-libpq-0.9.4.2...
setup: The program 'pg_config' is required but it could not be found.

cabal: Leaving directory '/tmp/cabal-tmp-30851/postgresql-libpq-0.9.4.2'
Starting     random-1.1
Building     network-2.8.0.0
Building     random-1.1
Completed    random-1.1
Completed    leancheck-0.9.1
Completed    network-2.8.0.0
Completed    primitive-0.6.4.0
cabal: Error: some packages failed to install:
libraft-0.3.0.0-5FPId3lfIs52enEKpp4HUU depends on libraft-0.3.0.0 which failed
to install.
postgresql-libpq-0.9.4.2-HyacS45qPUc33pszxfYdpM failed during the configure
step. The exception was:
ExitFailure 1
postgresql-simple-0.6-AUYYqF1Ip9i6KjeltQZU0G depends on postgresql-simple-0.6
which failed to install.