install plan9ports
put $PLAN9/bin LAST in your path

export HARVEY=/path/to/harvey
mkdir -p $HARVEY/linux_amd64/bin
ln -s ~/plan9port/bin/9c $HARVEY/linux_amd64/bin/pcc
cd /somewhere/to/build/9-cc
git clone -b harvey git@github.com:Harvey-OS/9-cc.git
cd 9-cc
mkdir -p Linux/amd64/lib
# from more INSTALL 
./configure
. ./env
mk
mk install
cp ./Linux/amd64/bin/iar $HARVEY/linux_amd64/bin/ar
cp ~/plan9port/bin/{sed, yacc,lex,awk,date} harvey/harvey/linux_amd64/bin
cp $PLAN/bin/awk $HARVEY/linux_amd64/bin/awk
cd sys/src
PATH=$HARVEY/linux_amd64/bin/:$PATH
sh BUILDTOOLCHAIN
export objtype=amd64
bash RUN_BUILD_IN_PRIVATE_NAMESPACE