llvm10 build failure on Rpi3

From: bob prohaska <fbsd_at_www.zefox.net>
Date: Wed, 23 Jun 2021 05:09:58 UTC
Attempts to compile devel/llvm10 on a RPi3 under poudriere using
poudriere bulk -J 2 -j main devel/llvm10 > bulk.log &
are failing with:

In file included from /wrkdirs/usr/ports/devel/llvm10/work/llvm-10.0.1.src/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp:45:
lib/Target/AMDGPU/AMDGPUGenGlobalISel.inc:11138:50: error: expected expression
        /*GIM_CheckRegBankForClass: @2779096485*/, /*MI*/0, /*Op*/1, /*RC*//*AMDGPU::SReg_64RegClassID: @2779096485*/,
                                                 ^
lib/Target/AMDGPU/AMDGPUGenGlobalISel.inc:11138:118: error: expected expression
        /*GIM_CheckRegBankForClass: @2779096485*/, /*MI*/0, /*Op*/1, /*RC*//*AMDGPU::SReg_64RegClassID: @2779096485*/,
                                                                                                                     ^
lib/Target/AMDGPU/AMDGPUGenGlobalISel.inc:11237:48: error: expected expression
      /*GIM_CheckRegBankForClass: @2779096485*/, /*MI*/0, /*Op*/0, /*RC*//*AMDGPU::VGPR_32RegClassID: @2779096485*/,
                                               ^
lib/Target/AMDGPU/AMDGPUGenGlobalISel.inc:11237:116: error: expected expression
      /*GIM_CheckRegBankForClass: @2779096485*/, /*MI*/0, /*Op*/0, /*RC*//*AMDGPU::VGPR_32RegClassID: @2779096485*/,
                                                                                                                   ^
4 errors generated.

Not sure if this is an ARM problem, a poudriere problem or an llvm10 problem.
It looks like an llvm10 problem to my eye.

The logfile is visible at
http://www.zefox.org/~bob/poudriere/data/logs/bulk/latest-per-pkg/llvm10/10.0.1_5/main-default.log
and the rest of the /usr/local/poudriere tree can be browsed as well. The
config files have links at the top directory.

The ports tree has been updated between attempts, if I'm reading the
poudriere-ports man page correctly those updates should be in effect.
If I'm not a hint how to update would be much appreciated. Ports live
in /usr/ports, owned by root. 

The goal of the enterprise is to compile www/chromium, which has worked
in the (distant) past using make. 

Thanks for reading,

bob prohaska