Use the version macros when building Setup.hs

The design called for allowing deps to be specified, and for the
Setup.hs to be able to use the same version macros as in other code.
This patch completes that second part.

cabal-install/Distribution/Client/SetupWrapper.hs

@@ -46,6 +46,8 @@ import Distribution.Simple.Compiler
          ( Compiler(compilerId), compilerFlavor, PackageDB(..), PackageDBStack )
 import Distribution.Simple.PreProcess
          ( runSimplePreProcessor, ppUnlit )
+import Distribution.Simple.Build.Macros
+         ( generatePackageVersionMacros )
 import Distribution.Simple.Program
          ( ProgramConfiguration, emptyProgramConfiguration
          , getProgramSearchPath, getDbProgramOutput, runDbProgram, ghcProgram
@@ -57,6 +59,7 @@ import Distribution.Simple.Program.Run
 import qualified Distribution.Simple.Program.Strip as Strip
 import Distribution.Simple.BuildPaths
          ( defaultDistPref, exeExtension )
+
 import Distribution.Simple.Command
          ( CommandUI(..), commandShowOptions )
 import Distribution.Simple.Program.GHC
@@ -548,7 +551,16 @@ externalSetupMethod verbosity options pkg bt mkargs = do
                       _     -> (ghcProgram,   ["-threaded"])
           cabalDep = maybe [] (\ipkgid -> [(ipkgid, cabalPkgid)])
                               maybeCabalLibInstalledPkgId
+
+          -- We do a few things differently once packages opt-in and declare
+          -- a custom-settup stanza. In particular we then enforce the deps
+          -- specified, but also let the Setup.hs use the version macros.
+          newPedanticDeps     = useDependenciesExclusive options'
+          selectedDeps
+            | newPedanticDeps = useDependencies options'
+            | otherwise       = useDependencies options' ++ cabalDep
           addRenaming (ipid, pid) = (ipid, pid, defaultRenaming)
+          cppMacrosFile = setupDir </> "setup_macros.h"
           ghcOptions = mempty {
               ghcOptVerbosity       = Flag verbosity
             , ghcOptMode            = Flag GhcModeMake
@@ -559,16 +571,17 @@ externalSetupMethod verbosity options pkg bt mkargs = do
             , ghcOptSourcePathClear = Flag True
             , ghcOptSourcePath      = toNubListR [workingDir]
             , ghcOptPackageDBs      = usePackageDB options''
-            , ghcOptHideAllPackages = Flag (useDependenciesExclusive options')
-            , ghcOptPackages        = toNubListR $
-                                        map addRenaming $
-                                        if useDependenciesExclusive options'
-                                          then useDependencies options'
-                                          else useDependencies options'
-                                                 ++ cabalDep
+            , ghcOptHideAllPackages = Flag newPedanticDeps
+            , ghcOptCabal           = Flag newPedanticDeps
+            , ghcOptPackages        = toNubListR $ map addRenaming selectedDeps
+            , ghcOptCppIncludes     = toNubListR [ cppMacrosFile
+                                                 | newPedanticDeps ]
             , ghcOptExtra           = toNubListR extraOpts
             }
       let ghcCmdLine = renderGhcOptions compiler ghcOptions
+      when newPedanticDeps $
+        rewriteFile cppMacrosFile (generatePackageVersionMacros
+                                     [ pid | (_ipid, pid) <- selectedDeps ])
       case useLoggingHandle options of
         Nothing          -> runDbProgram verbosity program conf ghcCmdLine