XOrg oriented build failure

[bch <brad.harder%gmail.com@localhost>]

[...]
dependall ===> external/mit/xorg/bin/xinit
dependall ===> external/mit/xorg/bin/xinput
#      link  xinput/xinput
/usr/src/obj/tooldir.NetBSD-7.99.54-amd64/bin/x86_64--netbsd-gcc
--sysroot=/usr/src/obj/destdir.amd64 -Wl,-rpath,/usr/X11R7/lib
-L=/usr/X11R7/lib  -pie  -shared-libgcc      -o xinput  buttonmap.o
feedback.o hierarchy.o list.o property.o setcp.o setint.o setmode.o
setptr.o state.o test.o test_xi2.o transform.o xinput.o
-Wl,-rpath-link,/usr/src/obj/destdir.amd64/lib  -L=/lib -lXi -lX11
-lXrandr -lXinerama -lm
hierarchy.o: In function `remove_master':
hierarchy.c:(.text+0xc2): undefined reference to `xi2_find_device_info'
hierarchy.c:(.text+0x226): undefined reference to `xi2_find_device_info'
hierarchy.c:(.text+0x253): undefined reference to `xi2_find_device_info'
hierarchy.o: In function `change_attachment':
hierarchy.c:(.text+0x30d): undefined reference to `xi2_find_device_info'
hierarchy.c:(.text+0x31c): undefined reference to `xi2_find_device_info'
hierarchy.o:hierarchy.c:(.text+0x3d4): more undefined references to
`xi2_find_device_info' follow
test_xi2.o: In function `test_xi2':
test_xi2.c:(.text+0x9f0): undefined reference to `print_classes_xi2'
transform.o: In function `map_to_output':
transform.c:(.text+0x2a3): undefined reference to `xi2_find_device_info'
collect2: error: ld returned 1 exit status

*** Failed target:  xinput
*** Failed command:
/usr/src/obj/tooldir.NetBSD-7.99.54-amd64/bin/x86_64--netbsd-gcc
--sysroot=/usr/src/obj/destdir.amd64 -Wl,-rpath,/usr/X11R7/lib
-L=/usr/X11R7/lib -pie -shared-libgcc -o xinput buttonmap.o feedback.o
hierarchy.o list.o property.o setcp.o setint.o setmode.o setptr.o
state.o test.o test_xi2.o transform.o xinput.o
-Wl,-rpath-link,/usr/src/obj/destdir.amd64/lib -L=/lib -lXi -lX11
-lXrandr -lXinerama -lm
*** Error code 1

Stop.
nbmake[9]: stopped in /usr/src/external/mit/xorg/bin/xinput

*** Failed target:  dependall
*** Failed command: cd "/usr/src/external/mit/xorg/bin/xinput";
/usr/src/obj/tooldir.NetBSD-7.99.54-amd64/bin/nbmake realall
*** Error code 1

Stop.
nbmake[8]: stopped in /usr/src/external/mit/xorg/bin/xinput
[...]