GXemul Code2

files to C++ (.c to .cc); it will of course be a major
undertaking to redesign the code so that it fits C++, but I
think it will be worth it. (main.c => main.cc only so far.)
Note: Release 0.4.6.1 will most likely be made from the code
base as it was yesterday, plus perhaps some documentation
updates.
Adding configure options "--with-gui" and "--without-gui";
autodetection of gtkmm-2.4 >= 2.12.1. A binary "gxemul-gui"
is hardlinked to "gxemul"; when started, it should (in the
future) bring up a GUI version of GXemul. For now, it just
displays a dummy GTK+ window.