Add support for some crazy X-* fields to Setup.hs

X-Install-Target:
    Since cabal doesn't have builtin support for installing executables
    to locations other than $bindir yet this allows me to install stuff
    into $libexec or any other directory.

X-Build-Depends-Like:
    Duplicating the dependencies of the main library for every test
    suite is getting annoying this allows me to copy the final resolved
    external dependencies of a component.

SetupCompat.hs

@@ -0,0 +1,104 @@
+{-# LANGUAGE CPP, RecordWildCards, StandaloneDeriving #-}
+module SetupCompat where
+
+import Control.Monad.State.Strict
+import Data.List
+import Data.Maybe
+import Data.Functor
+import Data.Function
+import Distribution.Simple.LocalBuildInfo
+import Distribution.PackageDescription
+
+#if __GLASGOW_HASKELL__ <= 706
+componentsConfigs ::
+    LocalBuildInfo -> [(ComponentName, ComponentLocalBuildInfo, [ComponentName])]
+componentsConfigs LocalBuildInfo {..} =
+    (maybe [] (\c -> [(CLibName, c, [])]) libraryConfig)
+    ++ ((\(n, clbi) -> (CExeName n, clbi, [])) <$> executableConfigs)
+    ++ ((\(n, clbi) -> (CTestName n, clbi, [])) <$> testSuiteConfigs)
+    ++ ((\(n, clbi) -> (CBenchName n, clbi, [])) <$> benchmarkConfigs)
+
+getComponent :: PackageDescription -> ComponentName -> Component
+getComponent pkg cname =
+    case lookupComponent pkg cname of
+      Just cpnt -> cpnt
+      Nothing   -> missingComponent
+  where
+    missingComponent =
+      error $ "internal error: the package description contains no "
+           ++ "component corresponding to " ++ show cname
+
+lookupComponent :: PackageDescription -> ComponentName -> Maybe Component
+lookupComponent pkg CLibName =
+    fmap CLib $ library pkg
+lookupComponent pkg (CExeName name) =
+    fmap CExe $ find ((name ==) . exeName) (executables pkg)
+lookupComponent pkg (CTestName name) =
+    fmap CTest $ find ((name ==) . testName) (testSuites pkg)
+lookupComponent pkg (CBenchName name) =
+    fmap CBench $ find ((name ==) . benchmarkName) (benchmarks pkg)
+
+-- We're lying here can't be bothered to order these
+allComponentsInBuildOrder :: LocalBuildInfo
+                          -> [(ComponentName, ComponentLocalBuildInfo)]
+allComponentsInBuildOrder lbi =
+      [ (cname, clbi) | (cname, clbi, _) <- componentsConfigs lbi ]
+
+getComponentLocalBuildInfo :: LocalBuildInfo -> ComponentName -> ComponentLocalBuildInfo
+getComponentLocalBuildInfo lbi cname =
+    case [ clbi
+         | (cname', clbi, _) <- componentsConfigs lbi
+         , cname == cname' ] of
+      [clbi] -> clbi
+      _      -> missingComponent
+  where
+    missingComponent =
+      error $ "internal error: there is no configuration data "
+           ++ "for component " ++ show cname
+
+deriving instance (Ord ComponentName)
+
+setComponentsConfigs
+    :: LocalBuildInfo
+    -> [(ComponentName, ComponentLocalBuildInfo, a)]
+    -> LocalBuildInfo
+setComponentsConfigs lbi cs = flip execState lbi $ mapM setClbis gcs
+ where
+--   gcs :: [ [(ComponentLocalBuildInfo, ComponentName, a)] ]
+   gcs = groupBy (sameKind `on` fst3) $ sortBy (compare `on` fst3) cs
+
+   fst3 (x,_,_) = x
+
+   sameKind CLibName CLibName = True
+   sameKind CLibName _ = False
+   sameKind (CExeName _) (CExeName _) = True
+   sameKind (CExeName _) _ = False
+   sameKind (CTestName _) (CTestName _) = True
+   sameKind (CTestName _) _ = False
+   sameKind (CBenchName _) (CBenchName _) = True
+   sameKind (CBenchName _) _ = False
+
+   setClbis [(CLibName, clbi, _)] =
+       get >>= \lbi -> put $ lbi {libraryConfig = Just clbi}
+
+   setClbis cs@((CExeName _, _, _):_) =
+       let cfg = (\((CExeName n), clbi, _) -> (n, clbi)) <$> cs in
+       get >>= \lbi -> put $ lbi {executableConfigs = cfg }
+
+   setClbis cs@((CTestName _, _, _):_) =
+       let cfg = (\((CTestName n), clbi, _) -> (n, clbi)) <$> cs in
+       get >>= \lbi -> put $ lbi {testSuiteConfigs = cfg }
+
+   setClbis cs@((CBenchName _, _, _):_) =
+       let cfg = (\((CBenchName n), clbi, _) -> (n, clbi)) <$> cs in
+       get >>= \lbi -> put $ lbi {benchmarkConfigs = cfg }
+
+#else
+
+setComponentsConfigs
+    :: LocalBuildInfo
+    -> [(ComponentName, ComponentLocalBuildInfo, [ComponentName])]
+    -> LocalBuildInfo
+setComponentsConfigs lbi cs = lbi { componentsConfigs = cs }
+
+#endif