bug#35743: applies more widely

[Robert Vollmert]

The problem seems more wide-spread, so should probably be fixed within 
import/cabal.scm.

E.g. warp:

http://hackage.haskell.org/package/warp-3.2.27/warp.cabal
http://hackage.haskell.org/package/streaming-commons-0.2.1.0/streaming-commons.cabal

contain things along the following lines:

benchmark builder-to-bytestring-io
    ...
    build-depends:  base
                  , bytestring >= 0.10.2
                  , gauge
                  , deepseq
                  , streaming-commons

  if flag(use-bytestring-builder)
    build-depends:     bytestring < 0.10.2.0
                     , bytestring-builder

This kind of out-dented conditional seems not very rare.