Log Message:
lcms2: update to 2.12

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2.12 Maintenance release
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Added new build-in sigmoidal tone curve
Added XCode 12 project
Added support for multichannel input up to 15 channels
Fix LUT8 write matrix
Fix version mess on 10/11
Fix tools & samples xgetopt
Fix warnings on different function pointers
Fix matlab MEX compilation
plugin: cleanup and better SSE detection
plugin: add lab to any on float
plugin: it can now be compiled as C++
recover PDF documentation, but try to keep it under a resonable size.
Prevent a rare but possible out-of-bounds read in postscript generator
Remove unused variables