Please add s390x to list of known architectures

[nomeata]

ghc-7.0.4 compiles and runs fine on s390x, after an initial bootstrap via ghc-6.4.2 (based on .hsc files built on s390 and the patches initially created for ppc64 found on  https://slyfox.ath.cx/ghc/patches/6.4.2/) and ghc-6.10.1 (which hit the bug mentioned in  http://haskell.1045720.n5.nabble.com/the-impossible-happened-splitTyConApp-td3148936.html#a3148937 once but manually building the files without -O helped, as SPJ said it would).

It would be great if bootstrapping ghc did not require that many detours.

Please apply the attached patch so that ghc knows about the new architecture.

[simonmar]

Applied: 559f375f05d45d813f8c4ef8d4a6cba5150226be