Add a new xorg module, to use with USE_XORG: xorg-macros. This module
pulls in devel/xorg-macros.
Convert all ports that depends on xorg-macros to use this USE_XORG.
Split up the long XORG_MODULES= list in bsd.xorg.mk to have only one module
on each line.
Add xorg-macros dependency to xorg-server.

Reviewed by: kwm, bapt
Obtained from: xorg development repo (partly)