re-apply 0660a79
update dfhack lua script for offset export
40.07-40.09 osx mem layouts, correct typo.
fix osx layouts
osx layouts?
fix #129
New checksums generated by v24.0. df40.07 and 40.08 didn't change.
remove invalid/duplicate setuid from main from #128
src/dfinstancelinux.cpp: call w_r_ptrace for syscall

Call write_raw_ptrace for syscall instead of write_raw; we need a
executable page. fixes #123.

Also, improve error messages.