GHCi-Options

Since we have `cabal repl`, how about a `GHCi-Options` field? I know, you prefer direct Cabal support to such `Options` fields that allow to pass anything.
Here is my use case: The package `synthesizer-llvm` requires a lot of FFI and this prohibits usage in GHCi unless you pass the `-fobject-code` option to GHCi.
I can run:

```
cabal repl --ghc-option=-fobject-code
```

But I want to enable this trick permanently, e.g. by adding this line to `synthesizer-llvm.cabal`:

```
GHCi-Options: -fobject-code
```