diff --git a/shake-ext.cabal b/shake-ext.cabal
--- a/shake-ext.cabal
+++ b/shake-ext.cabal
@@ -1,6 +1,6 @@
 cabal-version: 1.18
 name: shake-ext
-version: 2.7.0.3
+version: 2.7.0.4
 license: BSD3
 license-file: LICENSE
 copyright: Copyright: (c) 2018 Vanessa McHale
@@ -41,11 +41,10 @@
         Development.Shake.TH
     default-language: Haskell2010
     ghc-options: -Wall
-    build-tools: cpphs
     build-depends:
         base >=4.10 && <5,
         shake -any,
-        composition-prelude,
+        composition-prelude -any,
         directory -any,
         Cabal >=2.0,
         template-haskell -any
diff --git a/src/Development/Shake/C.hs b/src/Development/Shake/C.hs
--- a/src/Development/Shake/C.hs
+++ b/src/Development/Shake/C.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP             #-}
 {-# LANGUAGE PatternSynonyms #-}
 
 -- | This module provides functions for easy C builds of binaries, static
@@ -21,17 +20,28 @@
                            , cconfigToArgs
                            , ccToString
                            , ccFromString
+                           , getCDepends
                            , host
                            ) where
 
 import           Control.Monad
 import           Data.List                  (isPrefixOf, isSuffixOf)
-#if __GLASGOW_HASKELL__ < 804
 import           Data.Semigroup
-#endif
 import           Development.Shake
 import           Development.Shake.FilePath
+import           System.Directory           (removeFile)
 import           System.Info
+
+-- | Given C source code, return a list of included files. This makes a call to
+-- either @clang@ or @gcc@, so it should be used sparingly.
+getCDepends :: CCompiler -- ^ Should be either @gcc@ or @clang@.
+            -> String -- ^ C source code
+            -> Action [FilePath]
+getCDepends cc' src = do
+    liftIO $ writeFile "shake.c" src
+    (Stdout o) <- command [] (ccToString cc') ["-MM", "shake.c"]
+    liftIO $ removeFile "shake.c"
+    pure (drop 1 . filter (/= "/") $ words o)
 
 mkQualified :: Monoid a => Maybe a -> Maybe a -> a -> a
 mkQualified pre suff = h [f suff, g pre]
diff --git a/src/Development/Shake/CCJS.hs b/src/Development/Shake/CCJS.hs
--- a/src/Development/Shake/CCJS.hs
+++ b/src/Development/Shake/CCJS.hs
@@ -1,11 +1,7 @@
-{-# LANGUAGE CPP #-}
-
 module Development.Shake.CCJS ( ccjs
                               ) where
 
-#if __GLASGOW_HASKELL__ < 804
 import           Data.Semigroup
-#endif
 import           Development.Shake
 import           Development.Shake.FilePath
 import           System.Directory           (createDirectoryIfMissing)
diff --git a/src/Development/Shake/Cabal.hs b/src/Development/Shake/Cabal.hs
--- a/src/Development/Shake/Cabal.hs
+++ b/src/Development/Shake/Cabal.hs
@@ -1,5 +1,3 @@
-{-# LANGUAGE CPP #-}
-
 module Development.Shake.Cabal ( getCabalDeps
                                , getCabalDepsV
                                , getCabalDepsA
@@ -18,9 +16,7 @@
 import           Control.Monad
 import           Data.Foldable                         (toList)
 import           Data.Maybe                            (catMaybes)
-#if __GLASGOW_HASKELL__ < 804
 import           Data.Semigroup
-#endif
 import           Development.Shake                     hiding (doesFileExist)
 import qualified Development.Shake                     as Shake
 import           Distribution.ModuleName