gcc unwind build failure

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

#   compile  libgcc/unwind-dw2.o
/usr/src/obj/tooldir.NetBSD-7.99.26-amd64/bin/x86_64--netbsd-gcc -O2
-std=gnu99   -Werror     --sysroot=/usr/src/obj/destdir.amd64
-I/usr/src/external/gpl3/gcc/lib/libgcc/libgcc
-I/usr/src/external/gpl3/gcc/lib/libgcc/arch/x86_64
-I/usr/src/external/gpl3/gcc/usr.bin/gcc/arch/x86_64 -DIN_GCC
-DIN_LIBGCC2 -I/usr/src/external/gpl3/gcc/dist/libgcc
-I/usr/src/external/gpl3/gcc/dist/libgcc/.
-I/usr/src/external/gpl3/gcc/dist/libgcc/../gcc
-I/usr/src/external/gpl3/gcc/dist/libgcc/../include  -fpic
-fbuilding-libgcc -fno-stack-protector
-I/usr/src/external/gpl3/gcc/dist/gcc/config/i386
-I/usr/src/external/gpl3/gcc/dist/gcc/ginclude
-I/usr/src/external/gpl3/gcc/dist/libgcc
-I/usr/src/external/gpl3/gcc/dist/libgcc/config
-I/usr/src/external/gpl3/gcc/dist/libgcc/config/x86_64
-I/usr/src/external/gpl3/gcc/dist/gcc
-I/usr/src/external/gpl3/gcc/dist/include -I.
-I/usr/src/external/gpl3/gcc/usr.bin/backend/obj  -c -fexceptions
-Wno-stack-protector -o unwind-dw2.o
/usr/src/external/gpl3/gcc/dist/libgcc/unwind-dw2.c
In file included from /usr/src/external/gpl3/gcc/dist/libgcc/unwind-dw2.c:38:0:
/usr/src/external/gpl3/gcc/dist/libgcc/unwind-dw2.h:49:11: error:
'__LIBGCC_DWARF_FRAME_REGISTERS__' undeclared here (not in a function)
     } reg[__LIBGCC_DWARF_FRAME_REGISTERS__+1];
           ^

*** Failed target:  unwind-dw2.o
*** Failed command:
/usr/src/obj/tooldir.NetBSD-7.99.26-amd64/bin/x86_64--netbsd-gcc -O2
-std=gnu99 -Werror --sysroot=/usr/src/obj/destdir.amd64
-I/usr/src/external/gpl3/gcc/lib/libgcc/libgcc
-I/usr/src/external/gpl3/gcc/lib/libgcc/arch/x86_64
-I/usr/src/external/gpl3/gcc/usr.bin/gcc/arch/x86_64 -DIN_GCC
-DIN_LIBGCC2 -I/usr/src/external/gpl3/gcc/dist/libgcc
-I/usr/src/external/gpl3/gcc/dist/libgcc/.
-I/usr/src/external/gpl3/gcc/dist/libgcc/../gcc
-I/usr/src/external/gpl3/gcc/dist/libgcc/../include -fpic
-fbuilding-libgcc -fno-stack-protector
-I/usr/src/external/gpl3/gcc/dist/gcc/config/i386
-I/usr/src/external/gpl3/gcc/dist/gcc/ginclude
-I/usr/src/external/gpl3/gcc/dist/libgcc
-I/usr/src/external/gpl3/gcc/dist/libgcc/config
-I/usr/src/external/gpl3/gcc/dist/libgcc/config/x86_64
-I/usr/src/external/gpl3/gcc/dist/gcc
-I/usr/src/external/gpl3/gcc/dist/include -I.
-I/usr/src/external/gpl3/gcc/usr.bin/backend/obj -c -fexceptions
-Wno-stack-protector -o unwind-dw2.o
/usr/src/external/gpl3/gcc/dist/libgcc/unwind-dw2.c
*** Error code 1