diff --git a/pngcrush-build.patch b/pngcrush-build.patch
index e40a2dc..95efede 100644
--- a/pngcrush-build.patch
+++ b/pngcrush-build.patch
@@ -1,6 +1,11 @@
-diff -up pngcrush-1.6.10/pngcrush.c.fix pngcrush-1.6.10/pngcrush.c
---- pngcrush-1.6.10/pngcrush.c.fix	2008-08-25 21:00:08.000000000 +0200
-+++ pngcrush-1.6.10/pngcrush.c	2008-10-30 22:51:27.000000000 +0100
+---
+ pngcrush.c |    2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+Index: pngcrush-1.6.10/pngcrush.c
+===================================================================
+--- pngcrush-1.6.10.orig/pngcrush.c
++++ pngcrush-1.6.10/pngcrush.c
 @@ -2821,7 +2821,7 @@ int main(int argc, char *argv[])
  #if !defined(PNG_cHRM_SUPPORTED) || !defined(PNG_hIST_SUPPORTED) || \
      !defined(PNG_iCCP_SUPPORTED) || !defined(PNG_sCAL_SUPPORTED) || \
diff --git a/pngcrush.spec b/pngcrush.spec
index a01d391..abd8548 100644
--- a/pngcrush.spec
+++ b/pngcrush.spec
@@ -1,7 +1,7 @@
 Summary: Optimizer for PNG (Portable Network Graphics) files
 Name: pngcrush
 Version: 1.6.10
-Release: 5%{?dist}
+Release: 6%{?dist}
 License: zlib
 Group: Applications/File
 URL: http://pmt.sourceforge.net/pngcrush/
@@ -29,7 +29,7 @@ tRNS, iCCP, and textual chunks.
 %build
 rm -f z*.h crc32.h deflate.h inf*.h trees.h png*.h # force using system headers
 pngflags=$(pkg-config --cflags --libs libpng)
-gcc %{optflags} $pngflags -o pngcrush pngcrush.c
+gcc %{optflags} $pngflags -lz -o pngcrush pngcrush.c
 
 %install
 %{__rm} -rf %{buildroot}
@@ -44,6 +44,9 @@ gcc %{optflags} $pngflags -o pngcrush pngcrush.c
 %{_bindir}/pngcrush
 
 %changelog
+* Tue Feb 16 2010 Gerd Hoffmann <kraxel@redhat.com> - 1.6.10-6
+- Fix FTBFS (#565047).
+
 * Sun Jul 26 2009 Fedora Release Engineering <rel-eng@lists.fedoraproject.org> - 1.6.10-5
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_12_Mass_Rebuild