Installing ddl with cabal fails

[andorp]

First sympthom:

Preprocessing executable 'ddl-generate' for ddl-0.1.0.0...

Generate.hs:13:8:
    Could not find module ‘System.FilePath’
    It is a member of the hidden package ‘filepath-1.4.0.0@filep_KsGE6pHE5eZHSN90ZVax6A’.
    Perhaps you need to add ‘filepath’ to the build-depends in your .cabal file.
    Use -v to see a list of the files searched for.
cabal: Error: some packages failed to install:

After adding filepath to ddl.cabal:

Linking dist/build/ddl-generate/ddl-generate ...
setup-Simple-Cabal-1.22.4.0-x86_64-linux-ghc-7.10.2: LICENSE: does not exist
cabal: Error: some packages failed to install:
ddl-0.1.0.0 failed during the final install step. The exception was:
ExitFailure 1

After adding LICENSE file it compiles and installs.