/// -DNO_PREFETCH | Disable use of prefetch asm-instruction. You may need this to
/// | run on some very old machines.
///
+/// -DNO_SPINLOCK | Use mutex instead of spinlocks. This is much slower, so you
+/// | really don't want to do this in general case.
+///
/// -DUSE_POPCNT | Add runtime support for use of popcnt asm-instruction. Works
/// | only in 64-bit mode and requires hardware with popcnt support.
///