setupext.py contains the code: if gotit: print_status("Tkinter", "Tkinter: %s, Tk: %s, Tcl: %s" % (Tkinter.__version__, Tkinter.TkVersion, Tkinter.TclVersion)) Because I built from source, the Tkinter.__version__ value is '$Revision$'. It seems poor practice to assume specific formatting of this field. Also, I built my copy of Python using "ccache gcc" as the compiler. The matplotlib build gets confused by this and tries to link with: c++ gcc -pthread -shared build/temp.linux-x86_64-2.7/src/ft2font.o ... I suspect somewhere that the "ccache" part is split off and "c++" added. Regards, Neil