Also requires us to expose memleak when !DEVELOPER, however we only
ever used the memleak tracking when the LIGHTNINGD_DEV_MEMLEAK
environment variable was set, so keep that.
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).