I'm starting a new post because the one about Lcms2 is already too long.
Now ./configure works for me with --with-opencolorio. However, when I start CinGG for the first time, I get these lines:
[OpenColorIO Info]: Color management disabled. (Specify the $OCIO environment variable to enable.)
[ocio_616 @ 0x562a521bd680] Error: Config or arguments invalid.
[ocio_616 @ 0x562a521bd680] Input color space is null
[ocio_616 @ 0x562a521bd680] Display is null
[ocio_616 @ 0x562a521bd680] View is null
[ocio_616 @ 0x562a521bd680] Failed to create OCIO processor.
PluginFFilter::new_ffilter(ocio)
And the opencolorio filter doesn't show up. I'm not sure which environment variable to use. Trying to use $OCIO prevents CinGG from starting, saying that this variable doesn't exist.