[Aboriginal] dev-environment.sh depends on gnu coreutils

[John Spencer]

on my busybox install (sabotage linux):

~/qemu/system-image-sh4 $ HDBMEGS=2048 ./dev-environment.sh
./dev-environment.sh: line 44: truncate: command not found

i suspect there's a portable command that could be used instead, for example
dd if=/dev/zero of="$imagefile" bs=1 count=0 seek="$imagesize"
creates a spare file of the required size in 0.0 seconds.