--- configure.ac.libpng	2011-09-15 05:59:15.000000000 +0200
+++ configure.ac	2011-09-15 05:59:58.000000000 +0200
@@ -952,7 +952,7 @@
 if test "x$support_png" = "xyes"; then
     AC_CHECK_LIB(
         png,
-        png_check_sig,
+        png_sig_cmp,
         [],
         [support_png=no],
         [-lz -lm]
--- src/mpng.c.libpng	2011-09-15 06:02:02.000000000 +0200
+++ src/mpng.c	2011-09-15 06:02:13.000000000 +0200
@@ -113,7 +113,7 @@
 
     if (png_depth < 8){
       if (png_color_type == PNG_COLOR_TYPE_GRAY ){
-        png_set_gray_1_2_4_to_8(png_ptr);
+        png_set_expand_gray_1_2_4_to_8(png_ptr);
         png_row_bytes = png_width;
       }else{
         png_set_expand(png_ptr);