From cace2729411f9dff59df6680f6b1a7986f69b05e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Llu=C3=ADs=20Batlle=20i=20Rossell?= <viric@viric.name>
Date: Mon, 2 Jul 2012 20:18:48 +0200
Subject: [PATCH] opencv 2.1: fixing the build

Related to libpng versions, and the gcc change (ptrdiff_t vs std::ptrdiff_t)
---
 pkgs/development/libraries/opencv/2.1.nix | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/pkgs/development/libraries/opencv/2.1.nix b/pkgs/development/libraries/opencv/2.1.nix
index 6f422463db9..ea5b1313dc7 100644
--- a/pkgs/development/libraries/opencv/2.1.nix
+++ b/pkgs/development/libraries/opencv/2.1.nix
@@ -9,11 +9,17 @@ stdenv.mkDerivation rec {
     sha256 = "26061fd52ab0ab593c093ff94b5f5c09b956d7deda96b47019ff11932111397f";
   };
 
-  buildInputs = [ cmake gtk glib libjpeg libpng libtiff jasper ffmpeg pkgconfig
+  # The order is important; libpng should go before X libs, because they
+  # propagate the libpng 1.5 (and opencv wants libpng 1.2)
+  buildInputs = [ cmake libpng gtk glib libjpeg libtiff jasper ffmpeg pkgconfig
     xineLib gstreamer ];
 
   enableParallelBuilding = true;
 
+  patchPhase = ''
+    sed -i 's/ptrdiff_t/std::ptrdiff_t/' include/opencv/*
+  '';
+
   preConfigure = ''
     export NIX_CFLAGS_COMPILE="$NIX_CFLAGS_COMPILE -D__STDC_CONSTANT_MACROS "
   '';