Add 'nixpkgs/' from commit 'abf060725d7614bd3b9f96764262dfbc2f9c2199'

git-subtree-dir: nixpkgs
git-subtree-mainline: 4e31070265257dc67d120c27e0f75c2344fdfa9a
git-subtree-split: abf060725d7614bd3b9f96764262dfbc2f9c2199

1 files changed, 13 insertions, 0 deletions

diff --git a/nixpkgs/lib/fetchers.nix b/nixpkgs/lib/fetchers.nix
new file mode 100644
index 000000000000..1107353b51dd
--- /dev/null
+++ b/nixpkgs/lib/fetchers.nix
@@ -0,0 +1,13 @@
+# snippets that can be shared by multiple fetchers (pkgs/build-support)
+{ lib }:
+{
+
+  proxyImpureEnvVars = [
+    # We borrow these environment variables from the caller to allow
+    # easy proxy configuration.  This is impure, but a fixed-output
+    # derivation like fetchurl is allowed to do so since its result is
+    # by definition pure.
+    "http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy"
+  ];
+
+}