From c9bed891f607602bae0e57eecb179dd23116214c Mon Sep 17 00:00:00 2001
From: Peter Simons <simons@cryp.to>
Date: Wed, 20 Dec 2017 09:11:32 +0100
Subject: [PATCH] sane-backends: enable support for PNG

---
 pkgs/applications/graphics/sane/backends/generic.nix | 4 ++--
 pkgs/top-level/all-packages.nix                      | 1 +
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/pkgs/applications/graphics/sane/backends/generic.nix b/pkgs/applications/graphics/sane/backends/generic.nix
index 3ef23142b2e..5d35857f05e 100644
--- a/pkgs/applications/graphics/sane/backends/generic.nix
+++ b/pkgs/applications/graphics/sane/backends/generic.nix
@@ -1,5 +1,5 @@
 { stdenv, fetchurl
-, avahi, libjpeg, libusb1, libv4l, net_snmp
+, avahi, libjpeg, libusb1, libv4l, net_snmp, libpng
 , gettext, pkgconfig
 
 # List of { src name backend } attibute sets - see installFirmware below:
@@ -24,7 +24,7 @@ stdenv.mkDerivation {
     ++ stdenv.lib.optional (libusb1 != null) "--enable-libusb_1_0"
     ;
 
-  buildInputs = [ avahi libusb1 libv4l net_snmp ];
+  buildInputs = [ avahi libusb1 libv4l net_snmp libpng ];
   nativeBuildInputs = [ gettext pkgconfig ];
   enableParallelBuilding = true;
 
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index e932b267aa2..6ab29b7ee9a 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -19939,6 +19939,7 @@ with pkgs;
 
   xsane = callPackage ../applications/graphics/sane/xsane.nix {
     libpng = libpng12;
+    sane-backends = sane-backends.override { libpng = libpng12; };
   };
 
   xsw = callPackage ../applications/misc/xsw {