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     ghc-parser-0.2.0.3
Failed to install ghc-parser-0.2.0.3
Build log ( /home/builder/.cabal/logs/ghc-8.6.3/ghc-parser-0.2.0.3-EE3emlou8Ix221LL6d89X.log ):
cabal: Entering directory '/tmp/cabal-tmp-22246/ghc-parser-0.2.0.3'
Configuring ghc-parser-0.2.0.3...
cabal: The program 'cpphs' is required but it could not be found.

cabal: Leaving directory '/tmp/cabal-tmp-22246/ghc-parser-0.2.0.3'
cabal: Error: some packages failed to install:
ghc-parser-0.2.0.3-EE3emlou8Ix221LL6d89X failed during the configure step. The
exception was:
ExitFailure 1