Revert opam solver dependency changes

- Reverts the change to the monolithic `clingo` package in favor of the
  previous split between `clasp` and `gringo` since `opam` works with
  the latter but not (for some reason) with the former.

- Adds explicit non-support for Python in `gringo`. This is not necessary
  for opam.

- Forces usage of the `std::to_string` functions in the C++ standard
  library instead of the incomplete alternative implementations inside
  of the `gringo` sources.

pkgs/tools/misc/aspcud/default.nix

@@ -1,5 +1,5 @@
 { stdenv, fetchurl,
-  boost, clasp, cmake, clingo, re2c
+  boost, clasp, cmake, gringo, re2c
 }:
 
 let
@@ -14,11 +14,11 @@ stdenv.mkDerivation rec {
     sha256 = "029035vcdk527ssf126i8ipi5zs73gqpbrg019pvm9r24rf0m373";
   };
 
-  buildInputs = [ boost clasp cmake clingo re2c ];
+  buildInputs = [ boost clasp cmake gringo re2c ];
 
   buildPhase = ''
     cmake -DCMAKE_BUILD_TYPE=Release \
-      -DGRINGO_LOC=${clingo}/bin/gringo \
+      -DGRINGO_LOC=${gringo}/bin/gringo \
       -DCLASP_LOC=${clasp}/bin/clasp \
       -DENCODING_LOC=$out/share/aspcud/specification.lp \
       .

pkgs/tools/misc/clingo/default.nix

@@ -1,37 +0,0 @@
-{ stdenv, fetchFromGitHub,
-  bison, re2c, scons
-}:
-
-let
-  version = "5.1.0";
-in
-
-stdenv.mkDerivation rec {
-  name = "clingo-${version}";
-
-  src = fetchFromGitHub {
-    owner = "potassco";
-    repo = "clingo";
-    rev = "v${version}";
-    sha256 = "1rvaqqa8xfagsqxk45lax3l29sksijd3zvl662vpvdi1sy0d71xv";
-  };
-
-  buildInputs = [ bison re2c scons ];
-
-  buildPhase = ''
-    scons --build-dir=release
-  '';
-
-  installPhase = ''
-    mkdir -p $out/bin
-    cp build/release/{gringo,clingo,reify,lpconvert} $out/bin/
-  '';
-
-  meta = with stdenv.lib; {
-    description = "A grounder and solver for logic programs.";
-    homepage = http://potassco.org;
-    platforms = platforms.linux;
-    maintainers = [ maintainers.hakuch ];
-    license = licenses.gpl3Plus;
-  };
-}

pkgs/tools/misc/gringo/default.nix

@@ -0,0 +1,40 @@
+{ stdenv, fetchurl,
+  bison, re2c, scons
+}:
+
+let
+  version = "4.5.4";
+in
+
+stdenv.mkDerivation rec {
+  name = "gringo-${version}";
+
+  src = fetchurl {
+    url = "mirror://sourceforge/project/potassco/gringo/${version}/gringo-${version}-source.tar.gz";
+    sha256 = "16k4pkwyr2mh5w8j91vhxh9aff7f4y31npwf09w6f8q63fxvpy41";
+  };
+
+  buildInputs = [ bison re2c scons ];
+
+  patches = [
+    ./gringo-4.5.4-cmath.patch
+    ./gringo-4.5.4-to_string.patch
+  ];
+
+  buildPhase = ''
+    scons WITH_PYTHON= --build-dir=release
+  '';
+
+  installPhase = ''
+    mkdir -p $out/bin
+    cp build/release/gringo $out/bin/gringo
+  '';
+
+  meta = with stdenv.lib; {
+    description = "Converts input programs with first-order variables to equivalent ground programs";
+    homepage = http://potassco.sourceforge.net/;
+    platforms = platforms.linux;
+    maintainers = [ maintainers.hakuch ];
+    license = licenses.gpl3Plus;
+  };
+}

pkgs/tools/misc/gringo/gringo-4.5.4-cmath.patch

@@ -0,0 +1,11 @@
+--- gringo/libgringo/src/term.cc~	2016-07-12 23:56:10.593577749 -0400
++++ gringo/libgringo/src/term.cc	2016-07-12 23:52:35.169968338 -0400
+@@ -22,6 +22,8 @@
+ #include "gringo/logger.hh"
+ #include "gringo/graph.hh"
+ 
++#include <cmath>
++
+ namespace Gringo {
+ 
+ // {{{ definition of Defines

pkgs/tools/misc/gringo/gringo-4.5.4-to_string.patch

@@ -0,0 +1,11 @@
+--- gringo/libgringo/gringo/bug.hh~	2014-03-10 12:19:26.000000000 -0400
++++ gringo/libgringo/gringo/bug.hh	2016-11-12 07:51:55.288563663 -0500
+@@ -32,7 +32,7 @@
+ #define _GLIBCXX_MAKE_MOVE_ITERATOR(_Iter) std::make_move_iterator(_Iter)
+ #define _GLIBCXX_MAKE_MOVE_IF_NOEXCEPT_ITERATOR(_Iter) std::make_move_iterator(_Iter)
+ 
+-#ifdef MISSING_STD_TO_STRING
++#if 0
+ 
+ #include <sstream>
+ 

pkgs/top-level/all-packages.nix

@@ -876,7 +876,7 @@ in
 
   goa = callPackage ../development/tools/goa { };
 
-  clingo = callPackage ../tools/misc/clingo { };
+  gringo = callPackage ../tools/misc/gringo { };
 
   gti = callPackage ../tools/misc/gti { };