Remove unused linux-only header file.
Remove unused linux-only header file.

curieos/Slic3r,alexrj/Slic3r,curieos/Slic3r,curieos/Slic3r,pieis2pi/Slic3r,alexrj/Slic3r,curieos/Slic3r,curieos/Slic3r,alexrj/Slic3r,alexrj/Slic3r,pieis2pi/Slic3r,pieis2pi/Slic3r,curieos/Slic3r,alexrj/Slic3r,alexrj/Slic3r,pieis2pi/Slic3r,pieis2pi/Slic3r,pieis2pi/Slic3r