executable stack flag

[Edward Z. Yang]

I've gone ahead and fixed it, and referenced the patches in the ticket.

Cheers,
Edward

Excerpts from Jens Petersen's message of Mon Jul 08 21:36:42 -0700 2013:
> Hi,
> 
> We noticed [1] in Fedora that ghc (7.4 and 7.6) are linking executables
> (again [2]) with the executable stack flag set. I haven't starting looking
> at the ghc code yet but wanted to ask first if it is intentional/necessary?
>  (ghc-7.0 doesn't seem to do this.) Having the flag set is considered a bit
> of a security risk so it would be better if all generated executable did
> not have it set.
> 
> I did some very basic testing of various executables, clearing their
> flags [3] and they all seemed to run ok without the executable stack flag
> set but I can't claim to have tested very exhaustively. (I thought perhaps
> it might be related to TemplateHaskell for example but even those
> executables seem to work, though I am sure I have not exercised all the
> code paths.)
> 
> Does someone know the current status of this?
> Will anything break if the flag is not set?
> Is it easy to patch ghc to not set the flag?
> Does it only affect the NCG backend?
> 
> Thanks, Jens
> 
> [1] https://bugzilla.redhat.com/show_bug.cgi?id=973512
> [2] http://ghc.haskell.org/trac/ghc/ticket/703
> [3] using "execstack -c"