When using the libappindicator/gtk/unix Tray backend, the background
thread which calls gtk_main() is never destroyed. This means that we
detect a leaked thread as SDL_Quit().
Instead, tell gtk to shut down its main loop when no tray icons are
active. This fixes the issue here: SDL notices no leak, and repeatedly
creating / destroying tray icons seems to work fine.
Signed-off-by: David Gow <david@ingeniumdigital.com>
src/tray/unix/SDL_tray.c: In function 'get_tmp_filename':
src/tray/unix/SDL_tray.c:345: warning: format '%ld' expects type 'long int', but argument 2 has type 'size_t'
src/tray/unix/SDL_tray.c: In function 'get_appindicator_id':
src/tray/unix/SDL_tray.c:361: warning: format '%ld' expects type 'long int', but argument 3 has type 'unsigned int'
SDL_HINT_QUIT_ON_LAST_WINDOW_CLOSE will not fire if there are active tray icons. This impacts only applications that create tray icons, and that at least one icon outlives the last visible top-level window. SDL_EVENT_QUIT will fire when the last active tray is destroyed if there are no active windows.
