> modular-xorg-server installation has failure and it stops.
> 
> Regards,
> 
> 
> checking pkg-config is at least version 0.9.0... yes
> checking for XKBCOMP... gnome-config: not found
> gnome-config: not found
> configure: error: Package requirements (x11 xkbfile) were not met:
> 
> No package 'x11' found
> No package 'xkbfile' found

I guess your X11_TYPE is not set to modular. I don't know why building 
"x11/modular-xorg-server" doesn't detected that and complain. In your 
/etc/mk.conf try:

X11_TYPE=modular

(and do a "make clean clean-depends")