Fix processing of ghc-shared-options

Original patch was:
  Sun Oct  7 13:41:53 BST 2007  Thorkil Naur <naur@post11.tele.dk>
    * Fix processing of shared options
Re-recorded due to code churn

Distribution/PackageDescription/Parse.hs

@@ -357,7 +357,7 @@ binfoFieldDescrs =
            ghcProfOptions        (\val binfo -> binfo{ghcProfOptions=val})
  , listField   "ghc-shared-options"
            text               parseTokenQ
-           ghcProfOptions        (\val binfo -> binfo{ghcSharedOptions=val})
+           ghcSharedOptions      (\val binfo -> binfo{ghcSharedOptions=val})
  , optsField   "ghc-options"  GHC
            options            (\path  binfo -> binfo{options=path})
  , optsField   "hugs-options" Hugs