Defines starting with `s' in bsd/kern

• SECDAY bsd/kern/kern_time.c:218
• SECYR bsd/kern/kern_time.c:219
• SHSIZE bsd/kern/kern_exec.c:183
• SIGPROP bsd/kern/kern_sig.c:66
• snd bsd/kern/uipc_usrreq.c:176
• SPL_DEBUG bsd/kern/init_main.c:333
• STK_PARAMS bsd/kern/sys_generic.c:276