openbox-xdg-autostart.c : drop-in replacement for python script

I believe the openbox-xdg-autostart Python script is an ideal candidate for a C drop-in replacement.  After checking the obsession code I noticed it was from an older lxsession xdg-autostart.c.  So I made a new one using functions copied verbatim from 0.4.6.1 lxsession  xdg-autostart.c.  All it required was a couple declarations for compile, and create a new main() function that accepted the desktop name as an argument.  I was able to seamlessly replace the Python script executed from openbox-autostart shell script, and my .desktop's executed as expected.  The only thing left to do after these two commits, would be modifying the openbox-autostart script, but I thought it best best to get some feedback on this first.