ghc-options: -threaded breaks some arches

[Duncan Coutts]

On Thu, 2009-10-29 at 18:55 +1100, Trent W. Buck wrote:

> > Of course I’d prefer if cabal had automatic support for this. I guess is
> > does not ATM, so for now the flag is ok, and I’m hereby telling the
> > Cabal people about this :-)
> 
> Did a trac ticket ever get created for this?  This affects Darcs 2.3.0,
> so I'm about to add an -f-threaded to darcs.cabal for 2.4.0, because I
> don't know how to tell Cabal "use -threaded iff you can".

Looks like there's no ticket for it.

If you write a patch now then we can probably get it into Cabal-1.8.x to
be released with ghc-6.12.1. Otherwise it will almost certainly languish
with the 100+ other open tickets.

What you'd want to do is in the configure step for GHC to run "ghc
--info" and parse the result into a name/value pair list and keep that
in the Compiler data structure. Then during compile, if the package uses
-threaded in the ghc-options and "RTS ways" does not include "thr" (or
perhaps "Support SMP" is not "YES") then issue a warning and omit the
flag.

Duncan