In 1.84 we made 'tailscale set'/'tailscale up' error out if duplicate
command line flags are passed.
This broke some container configurations as we have two env vars that
can be used to set --accept-dns flag:
- TS_ACCEPT_DNS- specifically for --accept-dns
- TS_EXTRA_ARGS- accepts any arbitrary 'tailscale up'/'tailscale set'
flag.
We default TS_ACCEPT_DNS to false (to make the container behaviour more
declarative), which with the new restrictive CLI behaviour resulted in
failure for users who had set --accept-dns via TS_EXTRA_ARGS as the flag would be
provided twice.
This PR re-instates the previous behaviour by checking if TS_EXTRA_ARGS
contains --accept-dns flag and if so using its value to override TS_ACCEPT_DNS.
Updates tailscale/tailscale#16108
Signed-off-by: Irbe Krumina <irbe@tailscale.com>
