GitLab

* Also add missing fail-safe wrapper.

* malloc et al. can return NULL on zero-size allocations.
* this commit also reverts the dubious calling of calloc by xmalloc.

* Library headers should always use angle brackets unless an override is
  provided by the package.

* The "queue" data structure actually implements a set anyway and will
  be renamed subsequently.

* The "index" is now a member of the "enqueued" struct.
* The search operation uses a predicate passed as function pointer.

* This prevents accidentally closing the file early.
* Also: Replace cryptic reference notation.
* A newly opened file finish state is set to false by default.
** The write process must wait to receive a close command from each collector
   to prevent file truncation.