Use spawn_async instead of spawn_sync

The 'spawn_sync' function has been deprecated for a very long time now,
but we could never use its intended replacement as its Vala bindings
were broken [1]. The underlying problem had been identified in [2] a
while ago, but has only been recently fixed in [3] and is now available
in Vala's 0.56 branch.

Since we rely on the child PID as a fallback for opinionated users or
shells that are unaware of OSC 7, we have to pass a callback function to
the 'spawn_async' call so we can capture the PID which is no longer
supplied by the method itself.

[1] https://gitlab.gnome.org/GNOME/vte/issues/227
[2] https://gitlab.gnome.org/GNOME/vala/-/issues/721
[3] https://gitlab.gnome.org/GNOME/vala/-/commit/f058e9e828f494ebf8d60cabff7999f219048623

0 files changed, 0 insertions, 0 deletions