From 2c5851b633f386a1388a5436b42225b0dcbc454a Mon Sep 17 00:00:00 2001
From: Peter Simons <simons@cryp.to>
Date: Mon, 9 Sep 2013 10:38:27 +0200
Subject: [PATCH] Break an infinite recursion between flex and bison.

Flex needs bison, but bison's test suite also needs flex, so we use an
untested build of bison to bootstrap flex first.
---
 pkgs/top-level/all-packages.nix | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 216969cb1dd..3cde58bd2ad 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -3552,16 +3552,25 @@ let
 
   flex = flex2535;
 
-  flex2535 = callPackage ../development/tools/parsing/flex/flex-2.5.35.nix { };
+  flex2535 = callPackage ../development/tools/parsing/flex/flex-2.5.35.nix {
+    # Break infinite recursion: bison's test suite needs flex, so we
+    # use an untested bison build to build flex first.
+    yacc = bison.override { flex = null; };
+  };
 
-  flex2534 = callPackage ../development/tools/parsing/flex/flex-2.5.34.nix { };
+  flex2534 = callPackage ../development/tools/parsing/flex/flex-2.5.34.nix {
+    yacc = bison.override { flex = null; };
+  };
 
-  flex2533 = callPackage ../development/tools/parsing/flex/flex-2.5.33.nix { };
+  flex2533 = callPackage ../development/tools/parsing/flex/flex-2.5.33.nix {
+    yacc = bison.override { flex = null; };
+  };
 
   # Note: 2.5.4a is much older than 2.5.35 but happens first when sorting
   # alphabetically, hence the low priority.
   flex254a = lowPrio (import ../development/tools/parsing/flex/flex-2.5.4a.nix {
-    inherit fetchurl stdenv yacc;
+    inherit fetchurl stdenv;
+    yacc = bison.override { flex = null; };
   });
 
   m4 = gnum4;