[Cin] Build from git

[Andrea paz]

@Andrew
I used "git am --whitespace-ignore ..."
the patches 003, 007 and 0009 give error and I skipped them, the
compilation was successful and I found no error messages. I don't know
what to test though: am I using ffmpeg 4.4 or 5, with these patches?
How do I check it?

@Phyllis
I have added read support for DPX. I'm wondering, how do you make
render presets for the internal engine?
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