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.

Overload the name.

Replaces GLib's GError.

Replace g_strchug() calls with a cheaper implementation.

Don't open the music directory for each "lsinfo" call.  Get the list
of playlist files from the memory database.