This is coveraudiod, a simple daemon that plays typing sounds when using the Surface Pro 1/2 Touch Cover. These sounds are the same that are played under Windows. coveraudiod is designed to be run under a X11 session, and requires pulseaudio. To build, just do "make" and "sudo make install". The build requirements are Xlib (with XInput2), pulseaudio (with GLib support), GLib, and libsndfile.