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.

For Android pre-5.0 compatibility (#213).

Declare two named elements.  An enum should not be used as an array
index, as this is error prone.

Move code from the Vorbis and FLAC decoder plugins.

Avoid reversing the order after every update.

False if the vector was not modified.

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