M = XYZToRGBMatrix(xr, yr, xg, yg, xb, yb, xw, yw)
Build a 3x3 color space conversion (CSC) matrix for converting X,Y,Z
linear color value vectors into a RGB color space, by a matrix-vector
multiplication, ie. rgb = M * xyz;
The destination color space for the rgb (R,G,B) vector is defined by its
color gamut, which in turn is specified by the 2D CIE-1931 chromaticity
coordinates of the white-point (xw, yw) and the color primaries red,
green and blue (xr, yr), (xg, yg) and (xb, yb).
See also the function RGBToXYZMatrix() for building the inverse matrix
for mapping from a RGB space to the XYZ color space.