Feature request: flag for debugging symbols

Right not `stack` supports `--no-strip` and `--ghc-options="-g"` with which it's possible to get debugging symbols in the executable. However ...

1. cabal has it's own flag `--enable-debug-info` which i've been told sets `-g` and also `-enable-dwarf-unwind`. So to recreate this behaviour we get to the wieldy: `stack build --no-strip --ghc-options="-g -enable-dward-unwind"`. To just have something like `stack build --with-symbols` would be much nicer.
1. Using `--ghc-options` bypasses cabal code, now `Setup.hs` scripts don't get notified that debug symbols were requested. I'm calling cmake from my `Setup.hs` script and i would like to compile dependencies (C code) also with symbols depending on the configuration for my library.

On a side note ...

[This issue](https://github.com/commercialhaskell/stack/issues/1438) talks about passing configure options to `Setup.hs` and underlying Cabal code.

However it's closed with the implementation of https://github.com/commercialhaskell/stack/pull/4750

But that PR talks about configure options for Pantry. I don't quite get how that is related, but it makes me believe that the added feature can not be used for Cabal because it's for Pantry.