Set TMPDIR to a sane value in Optware startup script.
Try to set umask to a sane value in startup script.

umask probably doesn't exist in every pristine Android version.
Unfortunately, it neither exists in Optware busybox build, so we can
only try and hope. But otherwise I have Android 4.1 system which has
default umake of 077, i.e. if you did ipkg update as root, you won't
be able to ipkg list as user, which won't do, so we should try to sanitize
umask.