Up_gtkSystemInfo
Gets some infrmations about the system, the materials or some devices.
Prototype :
fun [I] S
- I : a flag to set the response :
- GTK_SYSINFO_WINDOWING : returns "X11" (if the system turns under X server) or "WIN32"
- GTK_SYSINFO_DISPLAYNAME : returns the name, if exists
- GTK_SYSINFO_BEEP : returns "beep" after a beep system emission
Return : S : depending on the flag, or nil if error / bad falg