toolchain/52825: cross-build failure on FreeBSD/amd64

[Shinichi Doyashiki <clare%csel.org@localhost>]

>Number:         52825
>Category:       toolchain
>Synopsis:       cross-build failure on FreeBSD/amd64
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    toolchain-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Dec 16 13:45:00 +0000 2017
>Originator:     Shinichi Doyashiki
>Release:        NetBSD 8.99.9 (as source)
>Organization:
	at home
>Environment:
System: 	FreeBSD/amd64 11.1
Architecture: x86_64
Machine: amd64
>Description:
	build.sh failes on FreeBSD/amd64 as following:

/export/stage/tools/bin/nbmtree \
	-def /export/stage/tmp/etc/mtree/NetBSD.dist \
	-N /export/stage/hack/src/etc/mtree/..  \
	-p /export/stage/destdir/amd64/ -C -k all \
	|  /export/stage/tools/bin/nbawk '/ optional/ {next} // {print}' \
	| /export/stage/tools/bin/nbcat -l \
	>> /export/stage/destdir/amd64/METALOG
nbcat: stdout: Operation not supported

>How-To-Repeat:
	run build.sh on FreeBSD with following script:

#!/bin/sh
date=`/bin/date +%Y%m%d`
workdir=`pwd`

echo "===> deleting objdir"
rm -rf   /export/stage/tmp
mkdir -p /export/stage/tmp
rm -rf   /export/stage/objdir
mkdir -p /export/stage/objdir
rm -rf   /export/stage/tools
mkdir -p /export/stage/tools
rm -rf   /export/stage/destdir
mkdir -p /export/stage/destdir

OBJMACHINE=yes
export OBJMACHINE
TOOLDIR=/export/stage/tools
export TOOLDIR

for machine in amd64 i386 evbarm sparc; do
  cd ${workdir}/src || exit

  releasedir=/export/stage/release/${date}
  destdir=/export/stage/destdir/${machine}
  objdir=/export/stage/tmp

  echo "===> deleting ${destdir}"
  rm -rf ${destdir}
  mkdir -p ${destdir}

  ./build.sh -m ${machine} -x -j4 \
        -U \
        -O ${objdir} \
        -D ${destdir} \
        -R ${releasedir} \
        release ${options} \
        2>&1 | tee ${workdir}/make-${machine}.log
done

>Fix:
	Unknown.