Ok so gdk_cairo_set_source_window() is only available in GTK 2.24 and higher... So cairo window sources are not available in lower than 2.24. Also had to add support for pixmaps as sources for Cairo... which works except it currently does not support the clipping mask, so no transparency yet.

#!/bin/sh
PLATFORM=`uname -s`

if [ $PLATFORM = "Darwin" ]
then
    mkdir -p dwtest.app/Contents/MacOS
    mkdir -p dwtest.app/Contents/Resources

    cp -f $1/mac/Info.plist dwtest.app/Contents
    cp -f $1/mac/PkgInfo dwtest.app/Contents
    cp -f dwtest dwtest.app/Contents/MacOS
fi