From 8a98cf97e92cecba4feda766f4b7ac36cd82f8ea Mon Sep 17 00:00:00 2001
From: Matthew Bauer <mjbauer95@gmail.com>
Date: Sun, 6 May 2018 15:44:24 -0500
Subject: [PATCH] lib.makeSearchPath: allow null in search path
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This makes things match ‘buildInputs’ where inputs are allowed to be
null.
---
 lib/strings.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/strings.nix b/lib/strings.nix
index e6df7d99cb2e..61babf0b1aa3 100644
--- a/lib/strings.nix
+++ b/lib/strings.nix
@@ -82,7 +82,7 @@ rec {
        => "//bin"
   */
   makeSearchPath = subDir: packages:
-    concatStringsSep ":" (map (path: path + "/" + subDir) packages);
+    concatStringsSep ":" (map (path: path + "/" + subDir) (builtins.filter (x: x != null) packages));
 
   /* Construct a Unix-style search path, using given package output.
      If no output is found, fallback to `.out` and then to the default.