gallium llvmpipe failure & NDEBUG on netbsd-11

[Paul Ripke <stix%stix.id.au@localhost>]

First off, congrats on netbsd-11! After tracking NetBSD since 0.8,
this was by far one of the smoother upgrades I've had.

Now to the issue I'm encountering. As my integrated Ryzen graphics
isn't supported, I'm relying on llvmpipe, which has been working fine
on netbsd-10. Under netbsd-11, *some* apps are crashing:

libEGL warning: DRI2: failed to authenticate
DefIdx 1 exceeds machine model writes for early-clobber renamable $ymm5, dead early-clobber renamable $ymm0 = VPGATHERDDYrm killed renamable $ymm5(tied-def 0), renamable $rcx, 1, killed renamable $ymm1, 0, $noreg, killed renamable $ymm0(tied-def 1) :: (load 32, align 1)
 (Try with MCSchedModel.CompleteModel set to false)incomplete machine model
UNREACHABLE executed at /home/netbsd/netbsd-11/src/external/apache2/llvm/librt/libLLVMCodeGen/../../lib/../dist/llvm/lib/CodeGen/TargetSchedule.cpp:246!
Abort (core dumped) 

So far, apps include prusaslicer, freecad, xroar. They do "run" (like
molasses) by passing GALLIUM_DRIVER=softpipe.

Looking at TargetSchedule.cpp, it appears this is not built with
NDEBUG - should it? I also see a macro REDEBUG used to control NDEBUG,
although I haven't traced the includes around.

-- 
Paul Ripke
"Great minds discuss ideas, average minds discuss events, small minds
 discuss people."
-- Disputed: Often attributed to Eleanor Roosevelt. 1948.