-O in 6.8.1-candidate

[Simon Peyton-Jones]

| By default cabal uses ghc -O to build projects, so you won't see any
| difference if you comment it out of the cabal file. You will however
| if you explicitly turn off optimisations:
|
|     ghc-options: -Onot

This is perhaps a bit confusing. Is it documented in the cabal manual?  It's not documented under ghc-options in the currently-online manual.  Are there any other flags there by default?

Simon