This inconsistency drove me totally crazy, it's really confusing
when it's inconsistent especially when you work on both Cycles and
Blender sides.
Shouldn;t cause merge PITA, it's whitespace changes only, Git should
be able to merge it nicely.
This to avoids build conflicts with libc++ on FreeBSD, these __ prefixed values
are reserved for compilers. I apologize to anyone who has patches or branches
and has to go through the pain of merging this change, it may be easiest to do
these same replacements in your code and then apply/merge the patch.
Ref T37477.
reviewed by Brecht, with help from Lukas.
Note: dot is reversed compared to Blender.
In Blender Normals point outside, while in Cycles they point inside.
If you use your own custom vector with the Normal Node you will see a difference.
If you feed it with object normals it should work just as good.
