Bug#968611: lintian: No SIGCHLD handler set when running on multiple package groups

[Felix Lechner <felix.lechner@lease-up.com>]

Package: lintian
Severity: important
Owner: Shengjing Zhu <shsj@debian.org>

The IO::Async heisenbug was mitigated for single package groups but
still occurs when multiple groups are run together. There are two ways
to mitigate the issue:

1. Provide an implementation of
Lintian::IO::Async::unpack_and_index_piped_tar that does not use
IO::Async.
2. For separate processes for each package group.

Thanks to Shengjing Zhu for catching this issue!

Kind regards
Felix Lechner