Explicitly enable strip chopping for large uncompressed TIFFs

[kmilos]

Helps #5370 (only works for uncompressed images)

[radarhere]

Would you be able to add a test, that fails without your change and passes with it?

[kmilos]

Ah, only internal TiffImagePlugin.ImageFileDirectory_v2 is ever used to parse the TIFF IFDs (in both Image.open() and TiffImagePlugin._load_libtiff(), there's no way to actually see how libtiff is re-interpreting the IFD as far as I can tell, so not really sure how to test this...

[radarhere]

https://linux.die.net/man/3/tifffdopen

The default behaviour, for backwards compatibility, is to enable strip chopping.

Is it possible that this PR doesn't actually do anything?

[kmilos]

I only know this: https://gitlab.com/libtiff/libtiff/-/blob/29219a5bd14040d60e376324a52ef91b68808143/libtiff/tif_open.c#L254-257

But it does seem the flags are initialized by default with the intention to do the chopping: https://gitlab.com/libtiff/libtiff/-/blob/29219a5bd14040d60e376324a52ef91b68808143/libtiff/tif_open.c#L161-164

However, there was also recent (not yet released) PR that seems to indicate the default wasn't working on libtiff CMake builds (which is what Pillow uses lately AFAIK): https://gitlab.com/libtiff/libtiff/-/merge_requests/271

If this is the behaviour Pillow was expecting, doesn't hurt to be explicit ;)

[radarhere]

Ok, if the default has been wrong in previous libtiff versions, then it seems like this would be good, as it will fix that.

[radarhere]

libtiff 4.4.0 has now been released, fixing the default behaviour.