ghc-head: fix configure phase to make sure the compiler knows how to use gmp properly

Start with version 7.9 of the compiler, the path to the gmp library must
now be passed to the top-level configure script.

pkgs/development/compilers/ghc/head.nix

@@ -9,24 +9,21 @@ stdenv.mkDerivation rec {
     sha256 = "0487x0rvpz6c47v9qvc7rgk3hnabmali6c66mzh2bizkgmy1qpk0";
   };
 
-  buildInputs = [ ghc perl gmp ncurses happy alex ];
-
-  enableParallelBuilding = true;
-
-  buildMK = ''
-    libraries/integer-gmp_CONFIGURE_OPTS += --configure-option=--with-gmp-libraries="${gmp}/lib"
-    libraries/integer-gmp_CONFIGURE_OPTS += --configure-option=--with-gmp-includes="${gmp}/include"
-    DYNAMIC_BY_DEFAULT = NO
-  '';
+  buildInputs = [ ghc perl ncurses happy alex ];
 
   preConfigure = ''
-    echo "${buildMK}" > mk/build.mk
+    echo >mk/build.mk "DYNAMIC_BY_DEFAULT = NO"
     sed -i -e 's|-isysroot /Developer/SDKs/MacOSX10.5.sdk||' configure
   '' + stdenv.lib.optionalString (!stdenv.isDarwin) ''
     export NIX_LDFLAGS="$NIX_LDFLAGS -rpath $out/lib/ghc-${version}"
   '';
 
-  configureFlags = "--with-gcc=${stdenv.gcc}/bin/gcc";
+  configureFlags = [
+    "--with-gcc=${stdenv.gcc}/bin/gcc"
+    "--with-gmp-includes=${gmp}/include" "--with-gmp-libraries=${gmp}/lib"
+  ];
+
+  enableParallelBuilding = true;
 
   # required, because otherwise all symbols from HSffi.o are stripped, and
   # that in turn causes GHCi to abort
@@ -35,11 +32,7 @@ stdenv.mkDerivation rec {
   meta = {
     homepage = "http://haskell.org/ghc";
     description = "The Glasgow Haskell Compiler";
-    maintainers = [
-      stdenv.lib.maintainers.marcweber
-      stdenv.lib.maintainers.andres
-      stdenv.lib.maintainers.simons
-    ];
+    maintainers = with stdenv.lib.maintainers; [ marcweber andres simons ];
     inherit (ghc.meta) license platforms;
   };