diff --git a/Stackage/Build.hs b/Stackage/Build.hs
index 58199e6a..bcc10868 100644
--- a/Stackage/Build.hs
+++ b/Stackage/Build.hs
@@ -21,7 +21,7 @@ defaultBuildSettings :: BuildSettings
 defaultBuildSettings = BuildSettings
     { sandboxRoot = "sandbox"
     , expectedFailuresBuild = defaultExpectedFailures
-    , extraArgs = ["-fnetwork23"]
+    , extraArgs = const ["-fnetwork23"]
     , testWorkerThreads = 4
     }
 
@@ -47,15 +47,12 @@ build settings' bp = do
     let installBuildTool tool = do
             putStrLn $ "Installing build tool: " ++ tool
             ec <- withBinaryFile "build-tools.log" WriteMode $ \handle -> do
-                let args = addCabalArgs settings
+                let args = addCabalArgs settings BSBuild
                          $ "install"
                          : ("--cabal-lib-version=" ++ libVersion)
                          : "--build-log=logs-tools/$pkg.log"
                          : "-j"
-                         : concat
-                            [ extraArgs settings
-                            , [tool]
-                            ]
+                         : [tool]
                 hPutStrLn handle ("cabal " ++ unwords (map (\s -> "'" ++ s ++ "'") args))
                 ph <- runCabal args handle
                 waitForProcess ph
@@ -71,14 +68,13 @@ build settings' bp = do
 
     putStrLn "Beginning Stackage build"
     ph <- withBinaryFile "build.log" WriteMode $ \handle -> do
-        let args = addCabalArgs settings
+        let args = addCabalArgs settings BSBuild
                  $ "install"
                  : ("--cabal-lib-version=" ++ libVersion)
                  : "--build-log=logs/$pkg.log"
                  : "-j"
                  : concat
-                    [ extraArgs settings
-                    , bpPackageList bp
+                    [ bpPackageList bp
                     ]
         hPutStrLn handle ("cabal " ++ unwords (map (\s -> "'" ++ s ++ "'") args))
         runCabal args handle
diff --git a/Stackage/Test.hs b/Stackage/Test.hs
index 88f3d39f..24b3f737 100644
--- a/Stackage/Test.hs
+++ b/Stackage/Test.hs
@@ -96,7 +96,7 @@ runTestSuite settings testdir (packageName, SelectedPackageInfo {..}) = do
 
     passed <- handle (\TestException -> return False) $ do
         getHandle WriteMode  $ run "cabal" ["unpack", package] testdir
-        getHandle AppendMode $ run "cabal" (addCabalArgs settings ["configure", "--enable-tests"]) dir
+        getHandle AppendMode $ run "cabal" (addCabalArgs settings BSTest ["configure", "--enable-tests"]) dir
         when spiHasTests $ do
             getHandle AppendMode $ run "cabal" ["build"] dir
             getHandle AppendMode $ runGhcPackagePath "cabal" ["test"] dir
diff --git a/Stackage/Types.hs b/Stackage/Types.hs
index aa1828f0..41c57a52 100644
--- a/Stackage/Types.hs
+++ b/Stackage/Types.hs
@@ -110,9 +110,11 @@ data SelectSettings = SelectSettings
     , stablePackages         :: Map PackageName (VersionRange, Maintainer)
     }
 
+data BuildStage = BSBuild | BSTest
+
 data BuildSettings = BuildSettings
     { sandboxRoot           :: FilePath
-    , extraArgs             :: [String]
+    , extraArgs             :: BuildStage -> [String]
     , expectedFailuresBuild :: Set PackageName
     , testWorkerThreads     :: Int
     -- ^ How many threads to spawn for running test suites.
diff --git a/Stackage/Util.hs b/Stackage/Util.hs
index 6cf89a7d..581532da 100644
--- a/Stackage/Util.hs
+++ b/Stackage/Util.hs
@@ -102,15 +102,15 @@ addCabalArgsOnlyGlobal rest
     : "--package-db=global"
     : rest
 
-addCabalArgs :: BuildSettings -> [String] -> [String]
-addCabalArgs settings rest
+addCabalArgs :: BuildSettings -> BuildStage -> [String] -> [String]
+addCabalArgs settings bs rest
     = addCabalArgsOnlyGlobal
     $ ("--package-db=" ++ packageDir settings)
     : ("--libdir=" ++ libDir settings)
     : ("--bindir=" ++ binDir settings)
     : ("--datadir=" ++ dataDir settings)
     : ("--docdir=" ++ docDir settings)
-    : extraArgs settings ++ rest
+    : extraArgs settings bs ++ rest
 
 -- | Modified environment that adds our sandboxed bin folder to PATH.
 getModifiedEnv :: BuildSettings -> IO [(String, String)]