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.

That '!' accidently got lost in commit
75582d47

D'oh!

Closes #162

Regression by commit 738583e3

Previously, only streams were saved with range and tags, but this is
necessary for all "partial" songs (e.g. CUE tracks).

Works around a build failure on Solaris because annoyingly, Solaris
reserves the name "queue".  This rename was pending anyway.

From now on, struct Song will be used by the database only, and
DetachedSong will be used by everybody else.  DetachedSong is easier
to use, but Song has lower overhead.

Replaces GLib's g_str_has_prefix().

Don't use IgnoreError() when there's an overload that does not try to
give us one.

Fix for a major memory leak.

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

Replaces GLib's GError.