draw_cliptest_tmp.h:180 "position[3] = zero / zero; /* MSVC doesn't accept 0.0 / 0.0 */" is wrong in my opinion. The NAN macro from math.h should be used instead "position[3] = NAN;" see man NAN. I believe zero/zero is against any programming language standard that I know.
Unfortunately msvc (at least pre 2013) doesn't support NAN. There's only one other method I can think of to do it there which would be to use a float/uint union, set the uint to some nan bit pattern then use the float part. No idea if it would actually work and not really nicer neither.
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