From f84715501453f17a481a918e45b33ad426d0be14 Mon Sep 17 00:00:00 2001
From: Samuel Dionne-Riel <samuel@dionne-riel.com>
Date: Thu, 9 Aug 2018 19:10:24 -0400
Subject: [PATCH] mruby: Fixes build on Linux

I'm not sure of the semantics of `gcc` vs. `ld` for linking, but it
makes the difference between working and:

```
/nix/store/gpc2wld1s0c6qzx9326cwn1wcx29xzsj-binutils-2.30/bin/ld: warning: cannot find entry symbol _start; defaulting to 0000000000401100
```
---
 pkgs/development/compilers/mruby/default.nix | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pkgs/development/compilers/mruby/default.nix b/pkgs/development/compilers/mruby/default.nix
index cf93d778383..be306488479 100644
--- a/pkgs/development/compilers/mruby/default.nix
+++ b/pkgs/development/compilers/mruby/default.nix
@@ -13,6 +13,10 @@ stdenv.mkDerivation rec {
 
   nativeBuildInputs = [ ruby bison ];
 
+  # Necessary so it uses `gcc` instead of `ld` for linking.
+  # https://github.com/mruby/mruby/blob/35be8b252495d92ca811d76996f03c470ee33380/tasks/toolchains/gcc.rake#L25
+  preBuild = if stdenv.isLinux then "unset LD" else null;
+
   installPhase = ''
     mkdir $out
     cp -R build/host/{bin,lib} $out