Fix ghc 7.4

3 files changed, 10 insertions, 0 deletions

diff --git a/.travis.yml b/.travis.yml
index 35d74d1..1448588 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,6 +9,8 @@ install:
   - echo $PATH
   - which cabal
   - cabal install -j --only-dependencies --enable-tests
+  - if [ -n "$(ghc --version | awk '{ print $8 }' | sed -n '/^7.4/p')" ]; then cabal install Cabal --constraint "Cabal == 1.16.*"; fi
+
 
 script:
   - touch ChangeLog # Create ChangeLog if we're not on the release branch
diff --git a/Distribution/Helper.hs b/Distribution/Helper.hs
index b06ffe4..1a4bc37 100644
--- a/Distribution/Helper.hs
+++ b/Distribution/Helper.hs
@@ -57,6 +57,7 @@ import Control.Monad.IO.Class
 import Control.Monad.State.Strict
 import Control.Monad.Reader
 import Control.Exception as E
+import Data.Char
 import Data.Monoid
 import Data.List
 import Data.Default
@@ -211,6 +212,10 @@ buildPlatform :: IO String
 buildPlatform = do
   exe  <- findLibexecExe "cabal-helper-wrapper"
   dropWhileEnd isSpace <$> readProcess exe ["print-build-platform"] ""
+ where
+   -- dropWhileEnd is not provided prior to base 4.5.0.0.
+   dropWhileEnd :: (a -> Bool) -> [a] -> [a]
+   dropWhileEnd p = foldr (\x xs -> if p x && null xs then [] else x : xs) []
 
 -- | This exception is thrown by all 'runQuery' functions if the internal
 -- wrapper executable cannot be found. You may catch this and present the user
diff --git a/cabal-helper.cabal b/cabal-helper.cabal
index 1fbaa63..887a16d 100644
--- a/cabal-helper.cabal
+++ b/cabal-helper.cabal
@@ -21,6 +21,9 @@ description:
     Furthermore the wrapper supports one special case namely reading a state
     file for Cabal itself. This is needed as Cabal compiles it's Setup.hs using
     itself and not using any version of Cabal installed in any package database.
+    .
+    @cabal-helper@ can compile with @Cabal >= 1.14@ but requires @Cabal >= 1.16@
+    at runtime.
 
 license:             AGPL-3
 license-file:        LICENSE