From 4c4ac578b2a6ebd226eb84956751432a1b25619a Mon Sep 17 00:00:00 2001
From: Tomas Hlavaty <tom@logand.com>
Date: Sun, 21 Oct 2018 01:19:34 +0200
Subject: [PATCH] sbcl: specify $SBCL_HOME only when necessary

---
 pkgs/development/compilers/sbcl/default.nix | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/pkgs/development/compilers/sbcl/default.nix b/pkgs/development/compilers/sbcl/default.nix
index 9cb6d58be16..334ecbb168b 100644
--- a/pkgs/development/compilers/sbcl/default.nix
+++ b/pkgs/development/compilers/sbcl/default.nix
@@ -98,13 +98,12 @@ stdenv.mkDerivation rec {
     EOF
   '';
 
-  # Specifying $SBCL_HOME is only truly needed with `purgeNixReferences = true`.
-  setupHook = writeText "setupHook.sh" ''
+  setupHook = stdenv.lib.optional purgeNixReferences (writeText "setupHook.sh" ''
     addEnvHooks "$targetOffset" _setSbclHome
     _setSbclHome() {
       export SBCL_HOME='@out@/lib/sbcl/'
     }
-  '';
+  '');
 
   meta = sbclBootstrap.meta // {
     inherit version;