diff -Nru qrencode-3.1.1.orig//configure.ac qrencode-3.1.1/configure.ac
--- qrencode-3.1.1.orig//configure.ac	2010-02-03 01:42:12.000000000 +0100
+++ qrencode-3.1.1/configure.ac	2011-08-08 12:27:17.283893858 +0200
@@ -36,7 +36,7 @@
  [build_tools=$withval], [build_tools=yes])
 AM_CONDITIONAL(BUILD_TOOLS, [test "x$build_tools" = "xyes" ])
 if test x$build_tools = xyes ; then
-	PKG_CHECK_MODULES(png, "libpng12")
+	PKG_CHECK_MODULES(png, "libpng")
 fi
 
 dnl --with-tests