The keysym-to-engine-key rule lived in ibus.c, xim/xim.c and gtk/main.c,
and the copies disagreed: GTK sent keypad digits as special keys while
IBus and XIM sent '1'..'9'. Modifiers were rebuilt bit by bit in two
places although Mmask already is the X core layout; only the virtual
Super bit (26) that GDK and IBus set needs folding. ipckey/ipcmod in
ipc.c serve the daemon, the module and the tests.
