And use it for `exposesecret-passphrase`. This is probably overly
cautious, but it makes me feel a little better that we won't leak it
to someone with read-only access.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Any file in this directory which is executable and whose name only
consists of alphanumeric characters, space, '.', '-' or '_' will be
automatically loaded when lightningd starts (unless suppressed with
commandline options).