Now, the base rules are composed from microfiles *.part. I see no other way to handle...
[xorg/xkeyboard-config] / rules / base.o_c.part
1 ! option                =       compat
2   grp_led:num           =       +leds(num)
3   grp_led:caps          =       +leds(caps)
4   grp_led:scroll        =       +leds(scroll)