pkg/50682: pkgsrc-2015Q4 modular-xorg-server doesn't build.

[ignatios%cs.uni-bonn.de@localhost]

>Number:         50682
>Category:       pkg
>Synopsis:       pkgsrc-2015Q4 modular-xorg-server doesn't build.
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jan 20 12:55:00 +0000 2016
>Originator:     ignatios%cs.uni-bonn.de@localhost
>Release:        NetBSD 6.1.5_PATCH
>Organization:
computer science department, university of Bonn, Germany
>Environment:
	
	
System: NetBSD random83 6.1.5_PATCH NetBSD 6.1.5_PATCH (XEN3PAE_DOMU) #10: Mon Oct 20 11:28:07 CEST 2014  ignatios%random84.cs.uni-bonn.de@localhost:/var/itch/sources/6.1/oi386/sys/arch/i386/compile/XEN3PAE_DOMU i386
	(the build environment is a pkg_comp chroot within that machine)
Architecture: i386
Machine: i386
>Description:
	x11/modular-xorg-server doesn't build. Log line tail is:

  CC       xfont.lo
  CCLD     libglx.la
  CC       glxdri2.lo
In file included from glxdri2.c:36:0:
/pkg_comp/obj/pkgsrc/x11/modular-xorg-server/default/.buildlink/include/GL/internal/dri_interface.h:46:22: error: redefinition of typedef 'drm_context_t'
/pkg_comp/obj/pkgsrc/x11/modular-xorg-server/default/.buildlink/include/libdrm/drm.h:72:22: note: previous declaration of 'drm_context_t' was here
/pkg_comp/obj/pkgsrc/x11/modular-xorg-server/default/.buildlink/include/GL/internal/dri_interface.h:47:22: error: redefinition of typedef 'drm_drawable_t'
/pkg_comp/obj/pkgsrc/x11/modular-xorg-server/default/.buildlink/include/libdrm/drm.h:73:22: note: previous declaration of 'drm_drawable_t' was here
/pkg_comp/obj/pkgsrc/x11/modular-xorg-server/default/.buildlink/include/GL/internal/dri_interface.h:48:30: error: redefinition of typedef 'drm_clip_rect_t'
/pkg_comp/obj/pkgsrc/x11/modular-xorg-server/default/.buildlink/include/libdrm/drm.h:829:30: note: previous declaration of 'drm_clip_rect_t' was here
Makefile:720: recipe for target 'glxdri2.lo' failed
gmake[1]: *** [glxdri2.lo] Error 1
gmake[1]: Leaving directory '/pkg_comp/obj/pkgsrc/x11/modular-xorg-server/default/xorg-server-1.17.4/glx'
Makefile:771: recipe for target 'all-recursive' failed
gmake: *** [all-recursive] Error 1
*** Error code 2

Stop.
make: stopped in /usr/pkgsrc/x11/modular-xorg-server

>How-To-Repeat:
	cd /usr/pkgsrc/x11/modular-xorg-server; make

>Fix:
	unknown