GHC does not properly detect arch triplet for sparc64-unknown-linux-gnu

[glaubitz]

GHC 9.10.x does not properly detect the arch triplet for sparc64-unknown-linux-gnu.

Using GHC 9.6.6, the command ghc --info |grep Target will print:

(experimental_sparc64-dchroot)glaubitz@stadler:~/ghc-exp/ghc-9.10.3$ /usr/bin/ghc --info| grep 'Target platform'
 ,("Target platform","sparc64-unknown-linux")
(experimental_sparc64-dchroot)glaubitz@stadler:~/ghc-exp/ghc-9.10.3$

When using GHC 9.10.3, the same command will return an unknown architecture:

(experimental_sparc64-dchroot)glaubitz@stadler:~/ghc-exp/ghc-9.10.3$ ./_build/stage0/bin/ghc --info| grep 'Target platform'
 ,("Target platform","unknown-unknown-linux")
(experimental_sparc64-dchroot)glaubitz@stadler:~/ghc-exp/ghc-9.10.3$

This has been reported upstream as well.