Hello,

it would be nice if GHC build correctly detects if it's running on amd64 platform or plain old i386 platform. The problem is that current config.guess returns in both cases i386-pc-solaris2.* string. Certainly there is a possibility to use isainfo -n to test for application supported instruction set, see:

karel@silence:~/vcs/ghc$ ./config.guess 
i386-pc-solaris2.11
karel@silence:~/vcs/ghc$ isainfo -n
amd64
karel@silence:~/vcs/ghc$ 

I'm just not sure if hacking configure.ac's code below

i[[3456]]86-*-solaris2*)
        HostPlatform=i386-unknown-solaris2 # hack again
        TargetPlatform=i386-unknown-solaris2
        BuildPlatform=i386-unknown-solaris2
        HostPlatform_CPP='i386_unknown_solaris2'
        HostArch_CPP='i386'
        HostVendor_CPP='unknown'
        HostOS_CPP='solaris2'
        ;;

and changing HostArch_CPP from 'i386' to 'x86_64' would be enough for the change.