sandbox.out

# cabal v1-sandbox init
Writing a default package environment file to <ROOT>/sandbox.dist/cabal.sandbox.config
Creating a new sandbox at <ROOT>/sandbox.dist/sandbox
# cabal v1-install
Resolving dependencies...
Configuring Cabal-1.2...
Preprocessing library for Cabal-1.2..
Building library for Cabal-1.2..
Installing library in <PATH>
Completed    Cabal-1.2
# cabal v1-sandbox add-source
# cabal v1-install
Resolving dependencies...
Configuring Cabal-2.0...
Preprocessing library for Cabal-2.0..
Building library for Cabal-2.0..
Installing library in <PATH>
Completed    Cabal-2.0
Failed to install custom-setup-1.0
cabal: Error: some packages failed to install:
custom-setup-1.0-KL06TzJxSBkDtcPp9Xd2v1 failed during the configure step. The exception was:
  ExitFailure 1