Here is the error while compiling:

make[2]: Entering directory `/home/mc7/xfce/xfce64-4.8.0/gtk+-2.16.4/gdk-pixbuf'
if /bin/sh ../libtool --mode=compile gcc -DHAVE_CONFIG_H -I. -I. -I.. -DG_LOG_DOMAIN=\"GdkPixbuf\" -DGDK_PIXBUF_COMPILATION -I.. -I.. -I../gdk-pixbuf -I../gdk-pixbuf -DGTK_SYSCONFDIR=\"/opt/xfce-4.8.0/etc\" -DGTK_VERSION=\"2.16.4\" -DGTK_BINARY_VERSION=\"2.10.0\" -DGTK_PREFIX=\"/opt/xfce-4.8.0\"  -DG_DISABLE_CAST_CHECKS -pthread -I/opt/xfce-4.8.0/include/glib-2.0 -I/opt/xfce-4.8.0/lib/glib-2.0/include    -DGDK_PIXBUF_ENABLE_BACKEND "-DPIXBUF_LIBDIR=\"/opt/xfce-4.8.0/lib/gtk-2.0/2.10.0/loaders\"" "-DBUILT_MODULES_DIR=\"./.libs\"" -I/opt/xfce-4.8.0/include -I/opt/xfce-4.8.0/include/libpng15 -DG_DISABLE_SINGLE_INCLUDES -DATK_DISABLE_SINGLE_INCLUDES -DGDK_PIXBUF_DISABLE_SINGLE_INCLUDES -DGTK_DISABLE_SINGLE_INCLUDES  -I/usr/X11R6/include  -DGDK_PIXBUF_DISABLE_DEPRECATED -g -O2 -Wall -MT io-png.lo -MD -MP -MF ".deps/io-png.Tpo" \
  -c -o io-png.lo `test -f 'io-png.c' || echo './'`io-png.c; \
then mv -f ".deps/io-png.Tpo" ".deps/io-png.Plo"; \
else rm -f ".deps/io-png.Tpo"; exit 1; \
fi
libtool: compile:  gcc -DHAVE_CONFIG_H -I. -I. -I.. -DG_LOG_DOMAIN=\"GdkPixbuf\" -DGDK_PIXBUF_COMPILATION -I.. -I.. -I../gdk-pixbuf -I../gdk-pixbuf -DGTK_SYSCONFDIR=\"/opt/xfce-4.8.0/etc\" -DGTK_VERSION=\"2.16.4\" -DGTK_BINARY_VERSION=\"2.10.0\" -DGTK_PREFIX=\"/opt/xfce-4.8.0\" -DG_DISABLE_CAST_CHECKS -pthread -I/opt/xfce-4.8.0/include/glib-2.0 -I/opt/xfce-4.8.0/lib/glib-2.0/include -DGDK_PIXBUF_ENABLE_BACKEND -DPIXBUF_LIBDIR=\"/opt/xfce-4.8.0/lib/gtk-2.0/2.10.0/loaders\" -DBUILT_MODULES_DIR=\"./.libs\" -I/opt/xfce-4.8.0/include -I/opt/xfce-4.8.0/include/libpng15 -DG_DISABLE_SINGLE_INCLUDES -DATK_DISABLE_SINGLE_INCLUDES -DGDK_PIXBUF_DISABLE_SINGLE_INCLUDES -DGTK_DISABLE_SINGLE_INCLUDES -I/usr/X11R6/include -DGDK_PIXBUF_DISABLE_DEPRECATED -g -O2 -Wall -MT io-png.lo -MD -MP -MF .deps/io-png.Tpo -c io-png.c  -fPIC -DPIC -o .libs/io-png.o
In file included from io-png.c:31:
/opt/xfce-4.8.0/include/png.h:1403: error: syntax error before "png_FILE_p"
io-png.c: In function `png_simple_error_callback':
io-png.c:182: error: dereferencing pointer to incomplete type
io-png.c: In function `gdk_pixbuf__png_image_load':
io-png.c:280: error: dereferencing pointer to incomplete type
io-png.c: In function `gdk_pixbuf__png_image_begin_load':
io-png.c:440: error: dereferencing pointer to incomplete type
io-png.c: In function `gdk_pixbuf__png_image_load_increment':
io-png.c:512: error: dereferencing pointer to incomplete type
io-png.c: In function `png_info_callback':
io-png.c:629: warning: long int format, different type arg (arg 5)
io-png.c:629: warning: long int format, different type arg (arg 6)
io-png.c: In function `png_error_callback':
io-png.c:732: error: dereferencing pointer to incomplete type
io-png.c: In function `real_save_png':
io-png.c:922: error: dereferencing pointer to incomplete type
make[2]: *** [io-png.lo] Error 1
make[2]: Leaving directory `/home/mc7/xfce/xfce64-4.8.0/gtk+-2.16.4/gdk-pixbuf'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/mc7/xfce/xfce64-4.8.0/gtk+-2.16.4/gdk-pixbuf'
make: *** [all] Error 2


guess I'm missing an include in io-png.c?? Just for testing I even changed to explicit paths.. 

include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include "/opt/xfce-4.8.0/include/pngconf.h"
#include "/opt/xfce-4.8.0/include/pnglibconf.h"
#include "/opt/xfce-4.8.0/include/png.h"
#include "/opt/xfce-4.8.0/include/glib-2.0/glib.h"
#include "gdk-pixbuf-private.h"
#include "gdk-pixbuf-io.h"


And it still errors out.. Can anyone help me with this specific error?

thanks,
Mike