Disallow these syscalls with EPERM, instead of having them raise
SIGSYS.

Closes: https://gitlab.gnome.org/GNOME/tracker-miners/-/issues/312

Don't duplicate function based on ifdef, and add helper functions
to start/stop the memory release timeout.

Currently, we attempt to release heap after the TrackerMinerFiles
went through all the files. However this is also the time when we
possibly spawn the extractor and let it go through unextracted files.
Of course, releasing the heap meanwhile the extractor is operating
(i.e. causing batch updates on the tracker-miner-fs-3 side) is
from pointless (heap space will be needed again) to "bad" (we have
to ask for this heap memory again).

But nowadays, the miner knows of the extraction progress, and forwards
it through TrackerMiner::status as its own. We can track these status
changes, and defer this timeout to a point where the whole miner
(incl. extractor) are idle.

This makes the heap release operation after miner activity happen
at a more effective and less awkward time.

Call malloc_trim when fully idle

See merge request https://gitlab.gnome.org/GNOME/tracker-miners/-/merge_requests/520

libtracker-miners-common: Disallow chmod/fchmod with soft errors

Closes #312

See merge request https://gitlab.gnome.org/GNOME/tracker-miners/-/merge_requests/516

For some ungodly reason, we may end up with Fontconfig indirectly
initialized (presumably from GStreamer modules). This library likes
to have access to its default config directory, otherwise resulting
in warnings like:

Fontconfig error: Cannot load default config file: Unable to open /etc/fonts/fonts.conf

Try to avoid this by allowing readonly access to this directory.

Closes: https://gitlab.gnome.org/GNOME/tracker-miners/-/issues/314

libtracker-miners-common: Allow readonly access to /etc/fonts

Closes #314

See merge request https://gitlab.gnome.org/GNOME/tracker-miners/-/merge_requests/522

Closes: https://gitlab.gnome.org/GNOME/tracker-miners/-/issues/323

tracker-miner-fs: Do not start during gnome-initial-setup process

Closes #323

See merge request https://gitlab.gnome.org/GNOME/tracker-miners/-/merge_requests/523

This boolean option is turned on by default, and allows disabling
the sandbox tests specifically.

Closes: https://gitlab.gnome.org/GNOME/tracker-miners/-/issues/308

build: Add sandbox_tests build option

Closes #308

See merge request https://gitlab.gnome.org/GNOME/tracker-miners/-/merge_requests/524