Disable FMA3 optimizations on x64

http://connect.microsoft.com/VisualStudio/feedbackdetail/view/893171/c000001d-illegal-instruction-on-msvcr120-log-0x2d3-on-x64

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Rename local variable to avoid collision with WinAPI function name

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>