Since we switched from autotools to Meson in commit
94592c1406, 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.
This completes the bug fix commit
2065e3290452377b2931f3129b230c8cc536cbc8; if we clear "queued" then we
must clear "queued_song" as well, or another variant of the assertion
fails.
When starting playback with a specific song which does not have the
highest priority, the previous highest priority song was skipped
completely because its order was "swapped". This commit changes to a
more expensive operation which inserts the selected song into the
order list.
This fixes a small part of #165
Our previous use of Queue::SwapOrders() could cause surprising
results:
- sometimes, the old "current" song would be played again (if the
newly selected song had not been played already)
- sometimes, the old "current" song would not be played again (if the
newly selected song had already been played)
This is inconsistent, because it should not depend on whether the
newly selected song had already been played.
So instead of Queue::SwapOrders() we now use Queue::MoveOrderAfter()
and Queue::MoveOrderBefore(), which is more expensive, but also more
consistent. It attempts to retain as much from the previous order
list as possible, and only moves the newly selected song around.
