Make program ready for GHC 8.2.1

[hansroland]

The program does not work under GHC 8.2.1:

roland@goms:~/Downloads/unix-2.7.2.2/unix-2.7.2-test$ cabal configure
Resolving dependencies...
Configuring unix-2.7.2.2...
configure: WARNING: unrecognized options: --with-compiler
checking for gcc... /usr/bin/gcc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.out

... lines deleted

config.status: creating include/HsUnixConfig.h
config.status: include/HsUnixConfig.h is unchanged
configure: WARNING: unrecognized options: --with-compiler
roland@goms:~/Downloads/unix-2.7.2.2/unix-2.7.2-test$ cabal-dependency-licenses
cabal-dependency-licenses: Saved package config file is outdated:
• the Cabal version changed from Cabal-2.0.0.2 to Cabal-1.24.2.0
Re-run the 'configure' command.
roland@goms:~/Downloads/unix-2.7.2.2/unix-2.7.2-test$ cabal --version
cabal-install version 2.0.0.0
compiled using version 2.0.0.2 of the Cabal library 
roland@goms:~/Downloads/unix-2.7.2.2/unix-2.7.2-test$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 8.2.1
roland@goms:~/Downloads/unix-2.7.2.2/unix-2.7.2-test$

Reason:
GHC 8.2.1 uses cabal version 2.0 however the program cabal-dependencies-licenses builds with cabal versions between 1.18 and 1.24

  Build-depends:
    Cabal      >= 1.18 && < 1.25,