build failure for pmax

[coypu%SDF.ORG@localhost]

Hi, I can get a build failure using:
./build.sh -j2 -m pmax -U -O ../obj kernel=INSTALL

Error being:
#   compile  INSTALL/cache_r4k.o
/usr/src/../obj/tooldir.NetBSD-7.99.33-amd64/bin/mipsel--netbsd-gcc -Wa,-msoft-float -G 0 -mno-abicalls -msoft-float -ffixed-24 -ffreestanding -fno-zero-initialized-in-bss -Os -mmemcpy -fno-strict-aliasing -fno-common -std=gnu99 -Werror -Wall -Wno-main -Wno-format-zero-length -Wpointer-arith -Wmissing-prototypes -Wstrict-prototypes -Wold-style-definition -Wswitch -Wshadow -Wcast-qual -Wwrite-strings -Wno-unreachable-code -Wno-pointer-sign -Wno-attributes -Wno-sign-compare --sysroot=/usr/src/../obj/destdir.pmax -Dpmax -I. -I/usr/src/sys/../common/lib/libx86emu -I/usr/src/sys/../common/include -I/usr/src/sys/arch -I/usr/src/sys -nostdinc -DMIPS1 -DMIPS3 -D_KERNEL -D_KERNEL_OPT -std=gnu99 -I/usr/src/sys/lib/libkern/../../../common/lib/libc/quad -I/usr/src/sys/lib/libkern/../../../common/lib/libc/string -I/usr/src/sys/lib/libkern/../../../common/lib/libc/arch/mips/string -c /usr/src/sys/arch/mips/mips/cache_r4k.c -o cache_r4k.o
In file included from /usr/src/sys/arch/mips/mips/cache_r4k.c:45:0:
./mips/cache_r4k.h: In function 'cache_op_r4k_line':
./mips/cache_r4k.h:69:2: error: asm operand 0 probably doesn't match constraints [-Werror]
  __asm volatile(
  ^
./mips/cache_r4k.h: In function 'cache_r4k_op_32lines_NN':
./mips/cache_r4k.h:129:2: error: asm operand 0 probably doesn't match constraints [-Werror]
  __asm volatile(
  ^
./mips/cache_r4k.h:129:2: error: asm operand 2 probably doesn't match constraints [-Werror]

I'm not sure what the reason for the complaint here is...

Secondary, cache operations do not seem to exist in CPUs before
MIPS32/64, is it a problem?

Thanks.