libfmt 10 doesn't know how to format a StringView, and doesn't cast to
std::string_view anymore.  The StringView class has been removed from
MPD 0.24 completely, and this is a stable-branch-only workaround.

Closes https://github.com/MusicPlayerDaemon/MPD/pull/1814

This should prevent ffmpeg from taking priority over the gme plugin.
The ffmpeg plugin is more buggy than gme.
One of the prominent bugs of preferring ffmpeg over gme is that ffmpeg
cannot seek SAP files while gme can. This should prevent that from
happening.

libfmt version 10 has difficulties formatting a `StringBuffer`, and we
need to help it by explicitly invoking the `c_str()` method.

libfmt version 10 apparently doesn't know how to format a
`StringBuffer`, failing the MPD build.  Since we have a formatter
specialization for `AudioFormat`, let's use that - it's better and
easier to use.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1807

Fixes assertion failure if the ZIP file contains a path that begins
with a slash.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1793

Fixes hide_playlist_targets not working after server restart

Currently, `hide_playlists_targets` works by skipping songs with
`in_playlist` value set to true in
[`Directory::Walk`](https://github.com/MusicPlayerDaemon/MPD/blob/a57bcd02382947abbd961594cdf00302c0c7866a/src/db/plugins/simple/Directory.cxx#L237). But
`in_playlist` is not stored and only updated in
[`UpdateWalk::PurgeDanglingFromPlaylists`](https://github.com/MusicPlayerDaemon/MPD/blob/a57bcd02382947abbd961594cdf00302c0c7866a/src/db/update/Playlist.cxx#L139),
which will only be executed while updating DB.

This causes the problem that playlist target songs are correctly
hidden after database update, but will remain visible after mpd server
restarted. This pr solves the problem by storing `in_playlist` value
of songs into the `SimpleDatabase` file.

This allows dropping a few compile-time version checks and we can use
pkg-config to detect the library.

This got lost 8 years ago in commit 87c88fcb

D'oh!

By default, if the parent of a process dies, the process gets SIGHUP
and is supposed to shut down.  This however doesn't work for MPD,
because MPD redefines SIGHUP with a different meaning (like most
daemons do).

To work around this, we configure the kernel to send SIGTERM instead
of SIGHUP.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1706

Fixes a busy loop in BufferingInputStream::RunThreadLocked() because
the method never learns that seeking is ignored, even though the HTTP
stream is already broken and can never be read; nobody cared to check
for errors.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1727

If the environment variable $HOME does not exist, don't attempt to
obtain it from /etc/passwd; without $HOME, the calling process
indicates that it does not wish MPD to access the home directory.

This also prevents MPD from attempting to load
`/root/.config/mpd/mpd.conf` if MPD got started as global systemd
service.  Reading from there makes no sense, only /etc/mpd.conf shall
be used then.

This piece of code was initially added by commit 5d857921.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1687

When drop_start_samples and drop_end_samples overlap and are greater
than the actual number of samples, the `num_samples` calculation in
SubmitPCM() could underflow.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1712

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1721

For CURLINFO_CONTENT_LENGTH_DOWNLOAD_T (commit 4efd0a9f).

CURLINFO_CONTENT_LENGTH_DOWNLOAD is deprecated and is ugly because it
uses floating point.

Fix build with Boost 1.81.0. `<array>` was included by one of those boost headers,
however, it's no longer included as of Boost 1.81.0.

`master` doesn't use `std::array` in this file.

While we're at it, add all necessary inclusion files.

These settings do not work if CURL was compiled with
CURL_DISABLE_PROXY, and cause error "An unknown option was passed in
to libcurl".

Fixes regression by commit 7ab0dfc8

Of course, mode=0700 is more secure, but allowing other users access
to new directories is a choice the user should make via umask().  If
the user-chosen umask allows everybody access, MPD should probably
respect that.

This is systemd specific, and Android doesn't have systemd.

The function spl_valid_name() should verify playlist names and prevent
path traversal, but it failed to do so on Windows, because it forgot
to check for backslashes.

This buggy piece of code was already present when stored playlists
were initially implemented in 2006 by commit 08003904, and
even during the many rounds of code refactoring, nobody ever bothered
to verify it.  D'oh!

(Thanks, Paul Arzelier)