curl -sS -L -O https://www.iana.org/time-zones/repository/releases/tzdata$DATA.tar.gz
tar xzf tzcode$CODE.tar.gz
tar xzf tzdata$DATA.tar.gz

if ! make CFLAGS=-DSTD_INSPIRED AWK=awk TZDIR=zoneinfo posix_only >make.out 2>&1; then
	cat make.out
	exit 2
fi

cd zoneinfo
../mkzip ../../zoneinfo.zip
cd ../..

files="update.bash zoneinfo.zip"
modified=true
if git diff --quiet $files; then
	modified=false
fi