Build patches for FreeBSD (as discussed in the former pull request #666)

- Cast the struct stat sb.st_ino field to machine_int_t explicitly to avoid a cast error in MP_OBJ_NEW_SMALL_INT(). This is necessary for FreeBSD, where st_ino is of different size
- If MP_CLOCKS_PER_SEC is defined on the target host, simply define CLOCK_DIV
  as a fraction, regardless of the value of MP_CLOCKS_PER_SEC.
  FreeBSD uses a non-POSIX compliant value of 128 for CLOCKS_PER_SEC