Expose X3FTOOLS and 6BY9RPI flags

[kmilos]

Synced w/ https://github.com/LibRaw/LibRaw-cmake/pull/18

To be merged on next LibRaw and LibRaw-cmake bump

[letmaik]

Do we really need them? I enabled both of them anyway for the binary wheels.

https://github.com/letmaik/rawpy/blob/master/setup.py#L190

[kmilos]

I reckon there will be custom builds and combos of both LibRaw and rawpy out there...

[letmaik]

Alright, I don't have a strong opinion on adding the two flags.

For this PR, could you bump LibRaw-cmake only and change https://github.com/letmaik/rawpy/blob/667a2ab7f2173086e30349553e1b29b5f6594329/setup.py#L190 and https://github.com/letmaik/rawpy/blob/667a2ab7f2173086e30349553e1b29b5f6594329/setup.py#L239 and https://github.com/letmaik/rawpy/blob/667a2ab7f2173086e30349553e1b29b5f6594329/.github/scripts/build-linux.sh#L69 to use the new CMake options?

Then this PR can be merged I think.

[letmaik]

Thanks! Can you do a quick test to check that the flags are indeed set?

[kmilos]

Sure, here it is on Windows:

Python 3.7.8 | packaged by conda-forge | (default, Jul 31 2020, 01:53:57) [MSC v.1916 64 bit (AMD64)]
Type 'copyright', 'credits' or 'license' for more information
IPython 7.18.1 -- An enhanced Interactive Python. Type '?' for help.

In [1]: import rawpy

In [2]: rawpy.flags
Out[2]:
{'DNGLOSSYCODEC': True,
 'DNGDEFLATECODEC': True,
 'OPENMP': True,
 'LCMS': False,
 'REDCINECODEC': False,
 'RAWSPEED': False,
 'DEMOSAIC_PACK_GPL2': False,
 'DEMOSAIC_PACK_GPL3': False,
 'X3FTOOLS': True,
 '6BY9RPI': True}