The following commands would add this plugin to your current source
snapshot of Scribus:

# ROOT=/usr/src/scribus_svn_trunk/Scribus/
# ln -s $(pwd) $ROOT/scribus/plugins/scripterng
# echo "ADD_SUBDIRECTORY(scripterng)" >> $ROOT/scribus/plugins/CMakeLists.txt
# cd $ROOT
# cmake .
# make
# make install

You can use this plug-in together with the old scripter. But on exit
it will raise an segfault. So you might want to remove scriptplugin from
CMakeLists.txt or you can deactivate it in the preferences.