From 1e04865e87c6d807db231a7ea485164c9c6cdecd Mon Sep 17 00:00:00 2001
From: Moritz Ulrich <moritz@tarn-vedra.de>
Date: Sat, 28 May 2016 12:46:16 +0200
Subject: [PATCH] buildRustPackage: Add `log-level` argument.

---
 pkgs/build-support/rust/default.nix | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pkgs/build-support/rust/default.nix b/pkgs/build-support/rust/default.nix
index 79e4366eebe1..9eebb53d5238 100644
--- a/pkgs/build-support/rust/default.nix
+++ b/pkgs/build-support/rust/default.nix
@@ -3,6 +3,7 @@
 , src ? null
 , srcs ? null
 , sourceRoot ? null
+, logLevel ? "warn"
 , buildInputs ? []
 , cargoUpdateHook ? ""
 , ... } @ args:
@@ -42,6 +43,7 @@ in stdenv.mkDerivation (args // {
     EOF
 
     export CARGO_HOME="$(realpath deps)"
+    export RUST_LOG=${logLevel}
 
     # Let's find out which $indexHash cargo uses for file:///dev/null
     (cd $sourceRoot && cargo fetch &>/dev/null) || true