Merge pull request #290 from edwtjo/ghc-parser-build-tools

ghc-parser: add missing build-tools directive

ghc-parser/ghc-parser.cabal

--- Initial ghc-parser.cabal generated by cabal init.  For further 
+-- Initial ghc-parser.cabal generated by cabal init.  For further
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                ghc-parser
 version:             0.1.3.0
 synopsis:            Haskell source parser from GHC.
--- description:         
+-- description:
 homepage:            https://github.com/gibiansky/IHaskell
 license:             MIT
 license-file:        LICENSE
 author:              Andrew Gibiansky
 maintainer:          andrew.gibiansky@gmail.com
--- copyright:           
+-- copyright:
 category:            Language
 build-type:          Custom
--- extra-source-files:  
+-- extra-source-files:
 cabal-version:       >=1.16
 
-extra-source-files: 
+build-tools:         happy, cpphs
+
+extra-source-files:
   build-parser.sh
   HaskellParser76.y.pp
   HaskellParser782.y.pp
@@ -25,8 +27,8 @@ extra-source-files:
 library
   exposed-modules:     Language.Haskell.GHC.Parser,
                        Language.Haskell.GHC.HappyParser
-  -- other-modules:       
-  -- other-extensions:    
+  -- other-modules:
+  -- other-extensions:
   build-depends:       base                 >=4.6 && <4.8,
                        ghc                  >=7.6 && <7.10