[PATCH acl] libmisc: __acl_get_uid(): fix memory wasting loop if user does not exist
I noticed that `acl_from_text()` unexpectedly returns ENOMEM for invalid user names. The reason for this is a missing break statement in the for loop in `__acl_get_uid()`, which causes the loop to act as if ERANGE was returned from `getpwnam_r()`, thereby exponentially increasing the buffer size to (in my case) multiple gigabytes, until `grow_buffer()` reports ENOMEM, which terminates the `__acl_get_uid()` function.
This is a pretty costly "no such user" lookup that can disturb a process's heap memory management, but can also cause a process to fail e.g. if it is multithreaded and other threads encounter an ENOMEM, before `__acl_get_uid()` frees the gigantic heap buffer and returns. The allocated memory isn't actually used. Therefore on Linux it should not affect other processes by default, due to its overcommit memory and lazy memory allocation strategy.
Fix this by properly terminating the for loop on any conditions except an ERANGE error being reported. The same break statement correctly exists in `__acl_get_gid()` already.
