diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,15 @@
 # cdeps
 
+## 0.1.2.1
+
+  * Improve backwards compatibility
+  * Minor performance improvements
+
+## 0.1.2.0
+
+  * Minor performance improvements
+  * Add `getIncludesText`
+
 ## 0.1.1.8
 
   * Fix build for GHC 8.2.2, 8.0.2 again.
diff --git a/cdeps.cabal b/cdeps.cabal
--- a/cdeps.cabal
+++ b/cdeps.cabal
@@ -1,6 +1,6 @@
 cabal-version: 1.18
 name: cdeps
-version: 0.1.1.8
+version: 0.1.2.2
 license: BSD3
 license-file: LICENSE
 copyright: Copyright: (c) 2018 Vanessa McHale
@@ -62,9 +62,13 @@
     default-language: Haskell2010
     ghc-options: -Wall
     build-depends:
-        base >=4.9 && <5,
+        base >=4.8 && <5,
         cdeps -any,
         optparse-applicative -any
+    
+    if !impl(ghc >=8.0)
+        build-depends:
+            semigroups -any
     
     if (flag(development) && impl(ghc <8.4))
         ghc-options: -Werror
diff --git a/src/Language/C/Dependency.x b/src/Language/C/Dependency.x
--- a/src/Language/C/Dependency.x
+++ b/src/Language/C/Dependency.x
@@ -1,22 +1,22 @@
 {
 {-# OPTIONS_GHC -fno-warn-unused-imports #-}
 module Language.C.Dependency ( getIncludes
+                             , getIncludesText
                              , getCDepends
                              , getAll
                              ) where
 
+import Control.Monad (filterM)
+import qualified Data.ByteString.Lazy as BSL
 import Data.Foldable (fold)
 import Data.List (groupBy, group, sort)
 import Data.Maybe (fromMaybe)
+import qualified Data.Text.Lazy as TL
+import Data.Text.Lazy.Encoding (decodeUtf8, encodeUtf8)
 import Control.Monad.IO.Class
 import System.Directory (doesFileExist)
-import Data.Bool (bool)
-import qualified Data.Text.Lazy as TL
-import Data.Text.Lazy.Encoding (decodeUtf8)
-import qualified Data.ByteString.Lazy as BSL
 import System.FilePath ((</>), takeDirectory)
 import System.Environment (lookupEnv)
-import Control.Monad
 
 }
 
@@ -60,6 +60,9 @@
 getIncludes :: BSL.ByteString -> Either String [FilePath]
 getIncludes = fmap extractDeps . lexC
 
+getIncludesText :: TL.Text -> Either String [FilePath]
+getIncludesText = getIncludes . encodeUtf8
+
 -- TODO file name??
 nested_comment :: Alex Token
 nested_comment = go 1 =<< alexGetInput
@@ -82,7 +85,7 @@
                                 Just (c',input_) -> go (addLevel c' $ n) input_
                         _ -> go n input'
 
-          addLevel c' = bool id (+1) (c'==42)
+          addLevel c' = if c' == 42 then (+1) else id
 
           err (pos,_,_,_) =
             let (AlexPn _ line col) = pos in
@@ -122,10 +125,10 @@
             -> m [FilePath]
 getCDepends incls src = liftIO $ do
     contents <- BSL.readFile src
-    envPath <- fromMaybe "" <$> lookupEnv "C_INCLUDE_PATH"
+    envPath <- lookupEnv "C_INCLUDE_PATH"
     let incl = includes' contents
         dir = takeDirectory src
-        allDirs = dir : incls ++ split envPath
+        allDirs = dir : incls ++ fromMaybe [] (split <$> envPath)
     filterM doesFileExist ((</>) <$> allDirs <*> incl)
 
 -- | Get transitive dependencies of a C source file.
@@ -138,6 +141,6 @@
     level <- traverse (getAll incls) deps
     let rmdups = fmap head . group . sort
         next = rmdups (fold (deps : level))
-    pure $ bool next deps (null level)
+    pure $ if null level then deps else next
 
 }