From b962caede7767bf4420fcb55224d02a46b6d5b30 Mon Sep 17 00:00:00 2001
From: Peter Simons <simons@cryp.to>
Date: Sun, 15 Sep 2013 22:05:16 +0200
Subject: [PATCH] bison-3.x: fix build for good this time

 - Bison 3.x no longer compiles without Perl.

 - Don't try to run the test suite unless flex is available.
---
 pkgs/development/tools/parsing/bison/3.x.nix | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pkgs/development/tools/parsing/bison/3.x.nix b/pkgs/development/tools/parsing/bison/3.x.nix
index ffc68a68f5f..e80f903db12 100644
--- a/pkgs/development/tools/parsing/bison/3.x.nix
+++ b/pkgs/development/tools/parsing/bison/3.x.nix
@@ -8,10 +8,10 @@ stdenv.mkDerivation rec {
     sha256 = "1ll22hcfslyl9n3pgvvphzdp18w9cyic8m0qimfnb8mrs1syrdz5";
   };
 
-  nativeBuildInputs = [ m4 ] ++ stdenv.lib.optionals doCheck [perl flex];
+  nativeBuildInputs = [ m4 perl ] ++ stdenv.lib.optionals doCheck [ flex ];
   propagatedBuildInputs = [ m4 ];
 
-  doCheck = true;
+  doCheck = flex != null;
 
   meta = {
     homepage = "http://www.gnu.org/software/bison/";