From d00775c1d9a3acbff2d121fbae54691a7f07d18a Mon Sep 17 00:00:00 2001
From: Thomas Gerbet <thomas@gerbet.me>
Date: Sun, 18 Aug 2024 14:18:02 +0200
Subject: [PATCH] stdenv: create `env-vars` file before writing data to it

This fixes the regression introduced by c47a1e701df7f00352b8cf401fa79c0d2f5fcc59
on Darwin. The creation of the file using `install` and process
substitution does not work on Darwin, you get the following complain:
```
install: skipping file '/dev/fd/63', as it was replaced while being copied
```

Fixes #335016
---
 pkgs/stdenv/generic/setup.sh | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/pkgs/stdenv/generic/setup.sh b/pkgs/stdenv/generic/setup.sh
index ef645e4e513e..1b4f7a89d358 100644
--- a/pkgs/stdenv/generic/setup.sh
+++ b/pkgs/stdenv/generic/setup.sh
@@ -1121,7 +1121,13 @@ substituteAllInPlace() {
 # the environment used for building.
 dumpVars() {
     if [ "${noDumpEnvVars:-0}" != 1 ]; then
-        install -m 0600 <(export 2>/dev/null) "$NIX_BUILD_TOP/env-vars" || true
+        # On darwin, install(1) cannot be called with /dev/stdin or fd from process substitution
+        # so first we create the file and then write to it
+        # See https://github.com/NixOS/nixpkgs/issues/335016
+        {
+            install -m 0600 /dev/null "$NIX_BUILD_TOP/env-vars" &&
+            export 2>/dev/null >| "$NIX_BUILD_TOP/env-vars"
+        } || true
     fi
 }