vanduino:
Yikes it's been 20 years since I had to untangle C indirect pointer addressing. Time for a beer.
...volatile uint8_t *SSDDR = &DDRL;
...
*SSDDR |= _BV(SS) ; // set SS as output
Wouldn't this be easier? ...
DDRL |= _BV (SS);
Or keep it readable:
pinMode (53, OUTPUT); // or whatever the pin was