From 5e5494a85213d535843e86e228f078381ab57459 Mon Sep 17 00:00:00 2001
From: zimbatm <zimbatm@zimbatm.com>
Date: Sun, 28 Feb 2016 13:27:43 +0000
Subject: [PATCH] make-wrapper.sh: add an --unset argument

`--set FOO ""` is not strictly equivalent to `--unset FOO`. In the former case
the environment variable still exists with an empty string as a value.
---
 pkgs/build-support/setup-hooks/make-wrapper.sh | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/pkgs/build-support/setup-hooks/make-wrapper.sh b/pkgs/build-support/setup-hooks/make-wrapper.sh
index 5150b4f0218..7d0f88abb85 100644
--- a/pkgs/build-support/setup-hooks/make-wrapper.sh
+++ b/pkgs/build-support/setup-hooks/make-wrapper.sh
@@ -19,6 +19,12 @@ makeWrapper() {
             echo "export $varName=$value" >> $wrapper
         fi
 
+        if test "$p" = "--unset"; then
+            varName=${params[$((n + 1))]}
+            n=$((n + 1))
+            echo "unset $varName" >> "$wrapper"
+        fi
+
         if test "$p" = "--run"; then
             command=${params[$((n + 1))]}
             n=$((n + 1))