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-1.2
Starting     IfElse-0.85
Starting     base-orphans-0.8.2
Starting     base-compat-0.11.1
Building     IfElse-0.85
Building     StateVar-1.2
Building     base-orphans-0.8.2
Building     base-compat-0.11.1
Completed    IfElse-0.85
Starting     brotli-0.0.0.0
Completed    StateVar-1.2
Starting     bz2-1.0.0.2
Building     brotli-0.0.0.0
Building     bz2-1.0.0.2
Completed    base-orphans-0.8.2
Starting     cabal-doctest-1.0.8
Building     cabal-doctest-1.0.8
Completed    brotli-0.0.0.0
Starting     colour-2.3.5
Building     colour-2.3.5
Completed    base-compat-0.11.1
Starting     composition-prelude-3.0.0.0
Completed    cabal-doctest-1.0.8
Starting     digest-pure-0.0.3
Building     composition-prelude-3.0.0.0
Building     digest-pure-0.0.3
Completed    composition-prelude-3.0.0.0
Starting     dir-traverse-0.2.2.3
Building     dir-traverse-0.2.2.3
Completed    digest-pure-0.0.3
Starting     dlist-0.8.0.8
Building     dlist-0.8.0.8
Completed    dir-traverse-0.2.2.3
Starting     exceptions-0.10.4
Building     exceptions-0.10.4
Completed    colour-2.3.5
Starting     fusion-plugin-types-0.1.0
Building     fusion-plugin-types-0.1.0
Completed    dlist-0.8.0.8
Starting     hashable-1.3.0.0
Completed    bz2-1.0.0.2
Starting     heaps-0.3.6.1
Building     hashable-1.3.0.0
Completed    fusion-plugin-types-0.1.0
Starting     integer-logarithms-1.0.3
Building     heaps-0.3.6.1
Building     integer-logarithms-1.0.3
Completed    exceptions-0.10.4
Starting     lz4-hs-0.1.4.1
Failed to install lz4-hs-0.1.4.1
Build log ( /home/builder/.cabal/logs/ghc-8.6.3/lz4-hs-0.1.4.1-1gZnFhUkmAJ8vEKCx0jyJg.log ):
cabal: Entering directory '/tmp/cabal-tmp-32175/lz4-hs-0.1.4.1'
Configuring lz4-hs-0.1.4.1...
cabal: The program 'c2hs' version >=0.28.6 is required but the version found
at /usr/bin/c2hs is version 0.28.3

cabal: Leaving directory '/tmp/cabal-tmp-32175/lz4-hs-0.1.4.1'
Starting     lzlib-1.0.7.0
Completed    integer-logarithms-1.0.3
Building     lzlib-1.0.7.0
Completed    hashable-1.3.0.0
Completed    heaps-0.3.6.1
Completed    lzlib-1.0.7.0
cabal: Error: some packages failed to install:
hstar-0.1.0.4-9YFmfBbDWK3Ji4r0QhKf0f depends on hstar-0.1.0.4 which failed to
install.
lz4-hs-0.1.4.1-1gZnFhUkmAJ8vEKCx0jyJg failed during the configure step. The
exception was:
ExitFailure 1