[fix] Don't crash on SDL < 2.9 (#1008)
[fix] Don't crash on SDL < 2.9 (#1008)

Otherwise we'll get an `undefined symbol` error, but this function is too convenient to bother with the old-fashioned way of rumbling.

Fixes <https://github.com/koreader/koreader/issues/5570>.
NiLuJe/koreader-base,koreader/koreader-base,NiLuJe/koreader-base,Frenzie/koreader-base,NiLuJe/koreader-base,Frenzie/koreader-base,Frenzie/koreader-base,Frenzie/koreader-base,koreader/koreader-base,NiLuJe/koreader-base,koreader/koreader-base,koreader/koreader-base