Local process crash via argument-buffer size underflow

Heap-based buffer overflow in entr 5.8 and earlier allows local users to corrupt process memory and crash the utility via crafted arguments. In run_utility(), strlcpy() reports each source's full length after copying into an ARG_MAX heap buffer, so an exact fill underflows the unsigned remaining count and permits later out-of-bounds writes. Exploitation requires a local user to invoke entr with a boundary-length argument set or a /_ token that expands to a longer pathname, and the documented consequence is memory corruption or process abort.