autodetect the python version in the Makefile (thx tab)

plugins/gtkgui/Makefile

 # Set the C flags to include the GTK+ and Python libraries
-CFLAGS = `pkg-config --cflags gtk+-2.0 pygtk-2.0` -I/usr/include/python2.4/ -I.
+PYTHONVER = `python -V 2>&1 | awk '{print $2}' | cut -f1,2 -d.`
+CFLAGS = `pkg-config --cflags gtk+-2.0 pygtk-2.0` -I/usr/include/python$(PYTHONVER) -I.
 LDFLAGS = `pkg-config --libs gtk+-2.0 pygtk-2.0`
 
 # Build the shared object