From efcb39233debaa9aa2d382c1710811bd71afda15 Mon Sep 17 00:00:00 2001
From: Vincent Laporte <Vincent.Laporte@gmail.com>
Date: Wed, 20 Dec 2017 22:43:24 +0000
Subject: [PATCH] ocaml: adds an argument to enable flambda

---
 pkgs/development/compilers/ocaml/generic.nix | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/pkgs/development/compilers/ocaml/generic.nix b/pkgs/development/compilers/ocaml/generic.nix
index 17b3033c31df..03ae6e518d0b 100644
--- a/pkgs/development/compilers/ocaml/generic.nix
+++ b/pkgs/development/compilers/ocaml/generic.nix
@@ -10,14 +10,18 @@ let
   safeX11 = stdenv: !(stdenv.isArm || stdenv.isMips);
 in
 
-{ stdenv, fetchurl, ncurses, buildEnv, libX11, xproto, useX11 ? safeX11 stdenv }:
+{ stdenv, fetchurl, ncurses, buildEnv
+, libX11, xproto, useX11 ? safeX11 stdenv
+, flambdaSupport ? false
+}:
 
 assert useX11 -> !stdenv.isArm && !stdenv.isMips;
+assert flambdaSupport -> stdenv.lib.versionAtLeast version "4.03";
 
 let
    useNativeCompilers = !stdenv.isMips;
-   inherit (stdenv.lib) optionals optionalString;
-   name = "ocaml-${version}";
+   inherit (stdenv.lib) optional optionals optionalString;
+   name = "ocaml${optionalString flambdaSupport "+flambda"}-${version}";
 in
 
 stdenv.mkDerivation (args // rec {
@@ -36,7 +40,9 @@ stdenv.mkDerivation (args // rec {
 
   prefixKey = "-prefix ";
   configureFlags = optionals useX11 [ "-x11lib" x11lib
-                                      "-x11include" x11inc ];
+                                      "-x11include" x11inc ]
+  ++ optional flambdaSupport "-flambda"
+  ;
 
   buildFlags = "world" + optionalString useNativeCompilers " bootstrap world.opt";
   buildInputs = [ncurses] ++ optionals useX11 [ libX11 xproto ];