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     base-prelude-1.3
Starting     base-orphans-0.8
Starting     base-compat-0.10.5
Building     StateVar-1.1.1.1
Building     base-prelude-1.3
Building     base-orphans-0.8
Building     base-compat-0.10.5
Completed    base-orphans-0.8
Starting     cabal-doctest-1.0.6
Completed    StateVar-1.1.1.1
Starting     cereal-0.5.8.0
Building     cabal-doctest-1.0.6
Building     cereal-0.5.8.0
Completed    cabal-doctest-1.0.6
Starting     cryptohash-md5-0.11.100.1
Building     cryptohash-md5-0.11.100.1
Completed    base-compat-0.10.5
Starting     cryptohash-sha1-0.11.100.1
Completed    base-prelude-1.3
Starting     data-bword-0.1.0.1
Building     cryptohash-sha1-0.11.100.1
Building     data-bword-0.1.0.1
Completed    cryptohash-md5-0.11.100.1
Starting     data-checked-0.3
Building     data-checked-0.3
Completed    data-bword-0.1.0.1
Starting     data-default-class-0.1.2.0
Completed    cryptohash-sha1-0.11.100.1
Starting     data-endian-0.1.1
Building     data-default-class-0.1.2.0
Completed    cereal-0.5.8.0
Starting     dlist-0.8.0.5
Building     data-endian-0.1.1
Completed    data-checked-0.3
Starting     entropy-0.4.1.4
Building     dlist-0.8.0.5
Completed    data-default-class-0.1.2.0
Starting     hashable-1.2.7.0
Completed    data-endian-0.1.1
Starting     integer-logarithms-1.0.2.2
Building     hashable-1.2.7.0
Building     integer-logarithms-1.0.2.2
Building     entropy-0.4.1.4
Completed    dlist-0.8.0.5
Starting     loch-th-0.2.2
Building     loch-th-0.2.2
Completed    integer-logarithms-1.0.2.2
Starting     network-info-0.2.0.10
Building     network-info-0.2.0.10
Completed    loch-th-0.2.2
Starting     placeholders-0.1
Building     placeholders-0.1
Completed    entropy-0.4.1.4
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
Completed    network-info-0.2.0.10
Starting     random-1.1
Completed    placeholders-0.1
Starting     semigroups-0.18.5
Building     random-1.1
Building     semigroups-0.18.5
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-27346/postgresql-libpq-0.9.4.2'
[1 of 1] Compiling Main             ( /tmp/cabal-tmp-27346/postgresql-libpq-0.9.4.2/dist/setup/setup.hs, /tmp/cabal-tmp-27346/postgresql-libpq-0.9.4.2/dist/setup/Main.o )
Linking /tmp/cabal-tmp-27346/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-27346/postgresql-libpq-0.9.4.2'
Starting     split-0.2.3.3
Building     split-0.2.3.3
Completed    semigroups-0.18.5
Completed    split-0.2.3.3
Completed    random-1.1
Completed    primitive-0.6.4.0
cabal: Error: some packages failed to install:
hasql-1.3.0.3-LLX4VYeFB85LWv1GHkeUrA depends on hasql-1.3.0.3 which failed to
install.
hasql-pool-0.5.0.1-JplwQ07XgftEQCsnR3Ln6Q depends on hasql-pool-0.5.0.1 which
failed to install.
postgresql-libpq-0.9.4.2-HyacS45qPUc33pszxfYdpM failed during the configure
step. The exception was:
ExitFailure 1