Default delay 5 seconds, configurable with --decklink-vout-nosignal-delay

podcast: be more tolerant with faulty feeds, so just ignore invalid items instead of refusing to the list the entire feed (close #8970)

drop patch not needed anymore

(same problem as XCB)

Pictures without destroy callback are allocated on the stack and never
explicitly released.

free(NULL)

...rather than the whole picture resource structure.

...rather than the whole picture resource structure.

These values are already zeroed a few lines above.

gc.p_sys can now be NULL, if the picture has no planes.