fficxx: automatic C++ binding generation

Warnings:

• The 'description' field should be longer than the 'synopsis' field. It's useful to provide an informative 'description' to allow Haskell programmers who have never heard about your package to understand the purpose of your package. The 'description' field content is typically shown by tooling (e.g. 'cabal info', Haddock, Hackage) below the 'synopsis' which serves as a headline. Please refer to <https://www.haskell.org/cabal/users-guide/developing-packages.html#package-properties> for more details.
• 'ghc-options: -O2' is rarely needed. Check that it is giving a real benefit and not just imposing longer compile times on your users.
• 'ghc-options/ghc-prof-options: -fprof*' profiling flags are typically not appropriate for a distributed library package. These flags are useful to profile this package, but when profiling other packages that use this one these flags clutter the profile output with excessive detail. If you think other packages really want to see cost centres from this package then use '-fprof-auto-exported' which puts cost centres only on exported functions. Alternatively, if you want to use this, make it conditional based on a Cabal configuration flag (with 'manual: True' and 'default: False') and enable that flag during development.