armv7 targeting via poudriere-devel: x11-toolkits/gnustep-back fails to build for undefined references to _Unwind_VRS_Get , __gnu_unwind_frame , and _Unwind_VRS_Set

Note: This was using an armv7 poudriere jail on a aarch64 machine able to
run armv7 code.

gnustep-back-0.28.0_1.log reports:

/usr/local/bin/ld.bfd: /usr/local/lib/libobjc.so: undefined reference to `_Unwind_VRS_Get(_Unwind_Context*, _Unwind_VRS_RegClass, unsigned int, _Unwind_VRS_DataRepresentation, void*)'
/usr/local/bin/ld.bfd: /usr/local/lib/libobjc.so: undefined reference to `__gnu_unwind_frame(_Unwind_Exception*, _Unwind_Context*)'
/usr/local/bin/ld.bfd: /usr/local/lib/libobjc.so: undefined reference to `_Unwind_VRS_Set(_Unwind_Context*, _Unwind_VRS_RegClass, unsigned int, _Unwind_VRS_DataRepresentation, void*)'
cc: error: linker command failed with exit code 1 (use -v to see invocation)
gmake[5]: *** [/usr/local/GNUstep/System/Library/Makefiles/Instance/tool.make:89: obj/gpbs] Error 1
gmake[4]: *** [/usr/local/GNUstep/System/Library/Makefiles/Instance/tool.make:74: internal-tool-all_] Error 2
gmake[3]: *** [/usr/local/GNUstep/System/Library/Makefiles/Master/rules.make:297: gpbs.all.tool.variables] Error 2
gmake[2]: *** [/usr/local/GNUstep/System/Library/Makefiles/Master/tool.make:71: internal-all] Error 2
gmake[2]: Leaving directory '/wrkdirs/usr/ports/x11-toolkits/gnustep-back/work/libs-back-back-0_28_0/Tools'
gmake[1]: *** [/usr/local/GNUstep/System/Library/Makefiles/Master/serial-subdirectories.make:53: internal-all] Error 2
gmake[1]: Leaving directory '/wrkdirs/usr/ports/x11-toolkits/gnustep-back/work/libs-back-back-0_28_0'
===> Compilation failed unexpectedly.
Try to set MAKE_JOBS_UNSAFE=yes and rebuild before reporting the failure to
the maintainer.
*** Error code 1

===
Mark Millard
marklmi at yahoo.com