Since we switched from autotools to Meson in commit
94592c14, we don't need to include
`config.h` early to properly enable large file support.  Meson passes
the required macros on the compiler command line instead of defining
them in `config.h`.

This means we can include `config.h` at any time, whenever we want to
check its macros, and there are no ordering constraints.

`HOST_NAME_MAX` is not a portable macro; it is undefined on some
systems.

Closes #402

std::regex_replace() is heavily bloated and overkill for this feature.

expand %h to the system hostname and default to a zeroconf string that
contains %h

Map LogLevel::INFO to G_LOG_LEVEL_INFO, and LogLevel::DEFAULT to
G_LOG_LEVEL_MESSAGE.  Now client connect/disconnect message are only
logged on log_level "secure".

Prepare to migrate away from GLib.  Currently, we're still using GLib
as a backend.

Use only ConfigData.hxx in plugin sources to reduce header
dependencies.

After we've been hit by Large File Support problems several times in
the past week (which only occur on 32 bit platforms, which I don't
have), this is yet another attempt to fix the issue.

This updates the copyright header to all be the same, which is
pretty much an update of where to mail request for a copy of the GPL
and the years of the MPD project. This also puts all committers under
'The Music Player Project' umbrella. These entries should go
individually in the AUTHORS file, for consistancy.

The variable "serviceName" is initialized with SERVICE_NAME, but was
overwritten with NULL when the setting is not configured.

config_get_string() is easier to use than config_get_param() because
it unpacks the config_param struct.

Renamed functions, types, variables.

To test if a string is empty, we can just see if the first byte is 0.
No need to include string.h for strlen() here.

Moved implementation specific code to their own sources, internal
declarations in zeroconf-internal.h.

If the configured avahi service name is invalid, abort MPD.  Don't
fall back to the default service name.