.arcconfig

lazymanifest: don't crash when out of memory (issue5916)

self->lines can be NULL if we failed to allocate memory for it.

{
    "conduit_uri": "https://phab.mercurial-scm.org/api",
    "repository.callsign": "HG",
    "arc.land.onto.default": "@",
    "base": "hg:.^"
}