On Sat, Jan 31, 2009 at 01:51:54AM +0100, Krzysztof Skrz??tnicki wrote:
> The following change in .cabal file may solve the problems:---
> flag base4
>   description: Choose base-4 if possible
>   default: True
>
> library
>   if flag(splitBase)
>     if flag(base4)
>       Build-Depends: base>=4, old-time, time, bytestring, containers,
> old-locale
>     else
>       Build-Depends: base>=3, old-time, time, bytestring, containers,
> old-locale
>   else
>     Build-Depends: base<3
>   Build-Depends: mtl, convertible >= 1.0.1, utf8-string
> ---
>
> It works for me and I *think* will also work for other setups, most notably
> GHC 6.8.*.

Not out of the box.  The base4 flag will be on by default for GHC
6.8.x too, and they'll get the base >= 4 dep, which will break.
They'd have to configure with the option to disable a flag (-f -base4
if memory serves), which is neither intuitive nor automatic.