Fix for png-1.5.

--- src-IL/src/il_icon.c.orig	Wed Jul  6 15:09:04 2011
+++ src-IL/src/il_icon.c	Wed Jul  6 15:10:14 2011
@@ -525,7 +525,7 @@ ILboolean ico_readpng_get_image(ICOIMAGE *Icon, ILdoub
 
 	// Expand low-bit-depth grayscale images to 8 bits
 	if (ico_color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
-		png_set_gray_1_2_4_to_8(ico_png_ptr);
+		png_set_expand_gray_1_2_4_to_8(ico_png_ptr);
 	}
 
 	// Expand RGB images with transparency to full alpha channels