diff -ruN sng-1.0.5/configure sng-1.0.5-patched//configure
--- sng-1.0.5/configure	2010-11-22 21:46:24.000000000 +0100
+++ sng-1.0.5-patched//configure	2011-02-12 19:50:15.000000000 +0100
@@ -4043,7 +4043,7 @@
 _ACEOF
 
 else
-    for dir in /etc/X11/ /usr/share/X11/rgb.txt /usr/X11R6/lib/X11 /usr/lib/X11 /usr/openwin/lib
+    for dir in /etc/X11/ /usr/share/X11/rgb.txt /usr/X11R6/lib/X11 /usr/lib/X11 /usr/openwin/lib /usr/X11/share/X11
     do
 	if test -f ${dir}/rgb.txt
 	then
--- a/sngd.c
+++ b/sngd.c
@@ -11,6 +11,18 @@
 #include "config.h"	/* for RGBTXT */
 #include "png.h"
 #include "sng.h"
+
+/* cope with API issues */
+#if PNG_LIBPNG_VER_MAJOR == 1
+  #if PNG_LIBPNG_VER_MINOR <= 2
+  #define TRANS_COLOR trans_values
+  #define TRANS_ALPHA trans
+  #endif
+  #if PNG_LIBPNG_VER_MINOR >= 4
+  #define TRANS_COLOR trans_color
+  #define TRANS_ALPHA trans_alpha
+  #endif
+#endif
 
 png_structp png_ptr;
 png_infop info_ptr;
@@ -794,17 +809,17 @@
 	fprintf(fpout, "tRNS {\n");
 	switch (info_ptr->color_type) {
 	case PNG_COLOR_TYPE_GRAY:
-	    fprintf(fpout, "    gray: %u;\n", info_ptr->trans_values.gray);
+	    fprintf(fpout, "    gray: %u;\n", info_ptr->TRANS_COLOR.gray);
 	    break;
 	case PNG_COLOR_TYPE_RGB:
 	    fprintf(fpout, "    red: %u; green: %u; blue: %u;\n",
-		    info_ptr->trans_values.red,
-		    info_ptr->trans_values.green,
-		    info_ptr->trans_values.blue);
+		    info_ptr->TRANS_COLOR.red,
+		    info_ptr->TRANS_COLOR.green,
+		    info_ptr->TRANS_COLOR.blue);
 	    break;
 	case PNG_COLOR_TYPE_PALETTE:
 	    for (i = 0; i < info_ptr->num_trans; i++)
-		fprintf(fpout, " %u", info_ptr->trans[i]);
+		fprintf(fpout, " %u", info_ptr->TRANS_ALPHA[i]);
 	    break;
 	case PNG_COLOR_TYPE_GRAY_ALPHA:
 	case PNG_COLOR_TYPE_RGB_ALPHA: