This adds color_chracteristics field in weston_output. This field is
intended to be set by compositor frontends and read by color managers.
Color managers can use this information when choosing the output color
space and dynamic range, particularly when no ICC profile has been set.
This is most useful for HDR outputs, where the HDR static metadata for
PQ mode or the display luminance parameters for HLG mode can be based on
color_characteristics.
The fields of weston_color_characteristics mirror the information
available in EDID. However, using EDID information as-is has several
caveats, so the decision to use EDID for this is left for the frontend
and ultimately to the end user.
There are no defined ranges or validity checks for this data. The color
manager will have to validate the values against whatever it is using
them for.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>