From 4a0a066f67b204315f8b3fa59e87f2634f26b7e9 Mon Sep 17 00:00:00 2001
From: Thomas Tuegel <ttuegel@mailbox.org>
Date: Thu, 20 Jul 2017 10:42:58 -0500
Subject: [PATCH] newt: unset CPP

Commit 093cc00cdd9d8cf31ecce5bc1dd3645c460a1b98 sets the CPP environment
variable by default, confusing the newt Makefile, which expects CPP=gcc for
computing dependencies.
---
 pkgs/development/libraries/newt/default.nix | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/pkgs/development/libraries/newt/default.nix b/pkgs/development/libraries/newt/default.nix
index 9002d06693e..e00decca2ff 100644
--- a/pkgs/development/libraries/newt/default.nix
+++ b/pkgs/development/libraries/newt/default.nix
@@ -16,6 +16,12 @@ stdenv.mkDerivation rec {
 
   NIX_LDFLAGS = "-lncurses";
 
+  preConfigure = ''
+    # If CPP is set explicitly, configure and make will not agree about which
+    # programs to use at different stages.
+    unset CPP
+  '';
+
   crossAttrs = {
     makeFlags = "CROSS_COMPILE=${stdenv.cc.prefix}";
   };